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<div class="SECT1">
- <h1 class="SECT1"><a name="CODING" id="CODING">4. Coding
- Guidelines</a></h1>
+ <h1 class="SECT1"><a name="CODING" id="CODING">4. Coding Guidelines</a></h1>
<div class="SECT2">
<h2 class="SECT2"><a name="S1" id="S1">4.1. Introduction</a></h2>
- <p>This set of standards is designed to make our lives easier. It is
- developed with the simple goal of helping us keep the "new and improved
- <span class="APPLICATION">Privoxy</span>" consistent and reliable. Thus
- making maintenance easier and increasing chances of success of the
- project.</p>
- <p>And that of course comes back to us as individuals. If we can
- increase our development and product efficiencies then we can solve
- more of the request for changes/improvements and in general feel good
- about ourselves. ;-></p>
+ <p>This set of standards is designed to make our lives easier. It is developed with the simple goal of helping us
+ keep the "new and improved <span class="APPLICATION">Privoxy</span>" consistent and reliable. Thus making
+ maintenance easier and increasing chances of success of the project.</p>
+ <p>And that of course comes back to us as individuals. If we can increase our development and product
+ efficiencies then we can solve more of the request for changes/improvements and in general feel good about
+ ourselves. ;-></p>
</div>
<div class="SECT2">
<h2 class="SECT2"><a name="S2" id="S2">4.2. Using Comments</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S3" id="S3">4.2.1. Comment, Comment,
- Comment</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Comment as much as possible without commenting the obvious. For
- example do not comment "variable_a is equal to variable_b". Instead
- explain why variable_a should be equal to the variable_b. Just
- because a person can read code does not mean they will understand why
- or what is being done. A reader may spend a lot more time figuring
- out what is going on when a simple comment or explanation would have
- prevented the extra research. Please help your fellow Privoxy
- developers out!</p>
- <p>The comments will also help justify the intent of the code. If the
- comment describes something different than what the code is doing
- then maybe a programming error is occurring.</p>
+ <h3 class="SECT3"><a name="S3" id="S3">4.2.1. Comment, Comment, Comment</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Comment as much as possible without commenting the obvious. For example do not comment "variable_a is equal
+ to variable_b". Instead explain why variable_a should be equal to the variable_b. Just because a person can
+ read code does not mean they will understand why or what is being done. A reader may spend a lot more time
+ figuring out what is going on when a simple comment or explanation would have prevented the extra research.
+ Please help your fellow Privoxy developers out!</p>
+ <p>The comments will also help justify the intent of the code. If the comment describes something different
+ than what the code is doing then maybe a programming error is occurring.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /* if page size greater than 1k ... */
+ <pre class="PROGRAMLISTING">/* if page size greater than 1k ... */
if (page_length() > 1024)
{
... "block" the page up ...
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S4" id="S4">4.2.2. Use blocks for
- comments</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Comments can help or they can clutter. They help when they are
- differentiated from the code they describe. One line comments do not
- offer effective separation between the comment and the code. Block
- identifiers do, by surrounding the code with a clear, definable
- pattern.</p>
+ <h3 class="SECT3"><a name="S4" id="S4">4.2.2. Use blocks for comments</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Comments can help or they can clutter. They help when they are differentiated from the code they describe.
+ One line comments do not offer effective separation between the comment and the code. Block identifiers do, by
+ surrounding the code with a clear, definable pattern.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /*********************************************************************
+ <pre class="PROGRAMLISTING">/*********************************************************************
* This will stand out clearly in your code!
*********************************************************************/
if (this_variable == that_variable)
</td>
</tr>
</table>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Exception:</i></span></p>
- <p>If you are trying to add a small logic comment and do not wish to
- "disrupt" the flow of the code, feel free to use a 1 line comment
- which is NOT on the same line as the code.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exception:</i></span></p>
+ <p>If you are trying to add a small logic comment and do not wish to "disrupt" the flow of the code, feel free
+ to use a 1 line comment which is NOT on the same line as the code.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S5" id="S5">4.2.3. Keep Comments on their
- own line</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>It goes back to the question of readability. If the comment is on
- the same line as the code it will be harder to read than the comment
- that is on its own line.</p>
- <p>There are three exceptions to this rule, which should be violated
- freely and often: during the definition of variables, at the end of
- closing braces, when used to comment parameters.</p>
+ <h3 class="SECT3"><a name="S5" id="S5">4.2.3. Keep Comments on their own line</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>It goes back to the question of readability. If the comment is on the same line as the code it will be
+ harder to read than the comment that is on its own line.</p>
+ <p>There are three exceptions to this rule, which should be violated freely and often: during the definition of
+ variables, at the end of closing braces, when used to comment parameters.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /*********************************************************************
+ <pre class="PROGRAMLISTING">/*********************************************************************
* This will stand out clearly in your code,
* But the second example won't.
*********************************************************************/
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S6" id="S6">4.2.4. Comment each logical
- step</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Logical steps should be commented to help others follow the intent
- of the written code and comments will make the code more
- readable.</p>
- <p>If you have 25 lines of code without a comment, you should
- probably go back into it to see where you forgot to put one.</p>
- <p>Most "for", "while", "do", etc... loops _probably_ need a comment.
- After all, these are usually major logic containers.</p>
+ <h3 class="SECT3"><a name="S6" id="S6">4.2.4. Comment each logical step</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Logical steps should be commented to help others follow the intent of the written code and comments will
+ make the code more readable.</p>
+ <p>If you have 25 lines of code without a comment, you should probably go back into it to see where you forgot
+ to put one.</p>
+ <p>Most "for", "while", "do", etc... loops _probably_ need a comment. After all, these are usually major logic
+ containers.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S7" id="S7">4.2.5. Comment All Functions
- Thoroughly</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>A reader of the code should be able to look at the comments just
- prior to the beginning of a function and discern the reason for its
- existence and the consequences of using it. The reader should not
- have to read through the code to determine if a given function is
- safe for a desired use. The proper information thoroughly presented
- at the introduction of a function not only saves time for subsequent
- maintenance or debugging, it more importantly aids in code reuse by
- allowing a user to determine the safety and applicability of any
- function for the problem at hand. As a result of such benefits, all
- functions should contain the information presented in the addendum
- section of this document.</p>
+ <h3 class="SECT3"><a name="S7" id="S7">4.2.5. Comment All Functions Thoroughly</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>A reader of the code should be able to look at the comments just prior to the beginning of a function and
+ discern the reason for its existence and the consequences of using it. The reader should not have to read
+ through the code to determine if a given function is safe for a desired use. The proper information thoroughly
+ presented at the introduction of a function not only saves time for subsequent maintenance or debugging, it
+ more importantly aids in code reuse by allowing a user to determine the safety and applicability of any
+ function for the problem at hand. As a result of such benefits, all functions should contain the information
+ presented in the addendum section of this document.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S8" id="S8">4.2.6. Comment at the end of
- braces if the content is more than one screen length</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Each closing brace should be followed on the same line by a
- comment that describes the origination of the brace if the original
- brace is off of the screen, or otherwise far away from the closing
- brace. This will simplify the debugging, maintenance, and readability
- of the code.</p>
- <p>As a suggestion , use the following flags to make the comment and
- its brace more readable:</p>
- <p>use following a closing brace: } /* -END- if() or while () or
- etc... */</p>
+ <h3 class="SECT3"><a name="S8" id="S8">4.2.6. Comment at the end of braces if the content is more than one
+ screen length</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Each closing brace should be followed on the same line by a comment that describes the origination of the
+ brace if the original brace is off of the screen, or otherwise far away from the closing brace. This will
+ simplify the debugging, maintenance, and readability of the code.</p>
+ <p>As a suggestion , use the following flags to make the comment and its brace more readable:</p>
+ <p>use following a closing brace: } /* -END- if() or while () or etc... */</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<div class="SECT2">
<h2 class="SECT2"><a name="S9" id="S9">4.3. Naming Conventions</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S10" id="S10">4.3.1. Variable
- Names</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Use all lowercase, and separate words via an underscore ('_'). Do
- not start an identifier with an underscore. (ANSI C reserves these
- for use by the compiler and system headers.) Do not use identifiers
- which are reserved in ANSI C++. (E.g. template, class, true, false,
- ...). This is in case we ever decide to port Privoxy to C++.</p>
+ <h3 class="SECT3"><a name="S10" id="S10">4.3.1. Variable Names</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Use all lowercase, and separate words via an underscore ('_'). Do not start an identifier with an
+ underscore. (ANSI C reserves these for use by the compiler and system headers.) Do not use identifiers which
+ are reserved in ANSI C++. (E.g. template, class, true, false, ...). This is in case we ever decide to port
+ Privoxy to C++.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- int msiis5hack = 0; int msIis5Hack = 0;</pre>
+ <pre class="PROGRAMLISTING">int msiis5hack = 0; int msIis5Hack = 0;</pre>
</td>
</tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S11" id="S11">4.3.2. Function
- Names</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Use all lowercase, and separate words via an underscore ('_'). Do
- not start an identifier with an underscore. (ANSI C reserves these
- for use by the compiler and system headers.) Do not use identifiers
- which are reserved in ANSI C++. (E.g. template, class, true, false,
- ...). This is in case we ever decide to port Privoxy to C++.</p>
+ <h3 class="SECT3"><a name="S11" id="S11">4.3.2. Function Names</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Use all lowercase, and separate words via an underscore ('_'). Do not start an identifier with an
+ underscore. (ANSI C reserves these for use by the compiler and system headers.) Do not use identifiers which
+ are reserved in ANSI C++. (E.g. template, class, true, false, ...). This is in case we ever decide to port
+ Privoxy to C++.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- int load_some_file(struct client_state *csp)</pre>
+ <pre class="PROGRAMLISTING">int load_some_file(struct client_state *csp)</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- int loadsomefile(struct client_state *csp)
+ <pre class="PROGRAMLISTING">int loadsomefile(struct client_state *csp)
int loadSomeFile(struct client_state *csp)</pre>
</td>
</tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S12" id="S12">4.3.3. Header file
- prototypes</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Use a descriptive parameter name in the function prototype in
- header files. Use the same parameter name in the header file that you
- use in the c file.</p>
+ <h3 class="SECT3"><a name="S12" id="S12">4.3.3. Header file prototypes</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Use a descriptive parameter name in the function prototype in header files. Use the same parameter name in
+ the header file that you use in the c file.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- (.h) extern int load_aclfile(struct client_state *csp);
+ <pre class="PROGRAMLISTING">(.h) extern int load_aclfile(struct client_state *csp);
(.c) int load_aclfile(struct client_state *csp)</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- (.h) extern int load_aclfile(struct client_state *); or
+ <pre class="PROGRAMLISTING">(.h) extern int load_aclfile(struct client_state *); or
(.h) extern int load_aclfile();
(.c) int load_aclfile(struct client_state *csp)</pre>
</td>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S13" id="S13">4.3.4. Enumerations, and
- #defines</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Use all capital letters, with underscores between words. Do not
- start an identifier with an underscore. (ANSI C reserves these for
- use by the compiler and system headers.)</p>
+ <h3 class="SECT3"><a name="S13" id="S13">4.3.4. Enumerations, and #defines</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Use all capital letters, with underscores between words. Do not start an identifier with an underscore.
+ (ANSI C reserves these for use by the compiler and system headers.)</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- (enumeration) : enum Boolean {FALSE, TRUE};
+ <pre class="PROGRAMLISTING">(enumeration) : enum Boolean {FALSE, TRUE};
(#define) : #define DEFAULT_SIZE 100;</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> We
- have a standard naming scheme for #defines that toggle a feature in
- the preprocessor: FEATURE_>, where > is a short (preferably 1
- or 2 word) description.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> We have a standard naming scheme for #defines
+ that toggle a feature in the preprocessor: FEATURE_>, where > is a short (preferably 1 or 2 word)
+ description.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</div>
<div class="SECT3">
<h3 class="SECT3"><a name="S14" id="S14">4.3.5. Constants</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
<p>Spell common words out entirely (do not remove vowels).</p>
- <p>Use only widely-known domain acronyms and abbreviations.
- Capitalize all letters of an acronym.</p>
- <p>Use underscore (_) to separate adjacent acronyms and
- abbreviations. Never terminate a name with an underscore.</p>
+ <p>Use only widely-known domain acronyms and abbreviations. Capitalize all letters of an acronym.</p>
+ <p>Use underscore (_) to separate adjacent acronyms and abbreviations. Never terminate a name with an
+ underscore.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<div class="SECT2">
<h2 class="SECT2"><a name="S15" id="S15">4.4. Using Space</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S16" id="S16">4.4.1. Put braces on a line
- by themselves.</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>The brace needs to be on a line all by itself, not at the end of
- the statement. Curly braces should line up with the construct that
- they're associated with. This practice makes it easier to identify
- the opening and closing braces for a block.</p>
+ <h3 class="SECT3"><a name="S16" id="S16">4.4.1. Put braces on a line by themselves.</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>The brace needs to be on a line all by itself, not at the end of the statement. Curly braces should line up
+ with the construct that they're associated with. This practice makes it easier to identify the opening and
+ closing braces for a block.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<p>if (this == that) { ... }</p>
<p>or</p>
<p>if (this == that) { ... }</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> In the
- special case that the if-statement is inside a loop, and it is
- trivial, i.e. it tests for a condition that is obvious from the
- purpose of the block, one-liners as above may optically preserve the
- loop structure and make it easier to read.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- developer-discretion.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Example
- exception:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> In the special case that the if-statement is
+ inside a loop, and it is trivial, i.e. it tests for a condition that is obvious from the purpose of the block,
+ one-liners as above may optically preserve the loop structure and make it easier to read.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> developer-discretion.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Example exception:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S17" id="S17">4.4.2. ALL control
- statements should have a block</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Using braces to make a block will make your code more readable and
- less prone to error. All control statements should have a block
- defined.</p>
+ <h3 class="SECT3"><a name="S17" id="S17">4.4.2. ALL control statements should have a block</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Using braces to make a block will make your code more readable and less prone to error. All control
+ statements should have a block defined.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<p>if (this == that) do_something(); do_something_else();</p>
<p>or</p>
<p>if (this == that) do_something();</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
- first example in "Instead of" will execute in a manner other than
- that which the developer desired (per indentation). Using code braces
- would have prevented this "feature". The "explanation" and
- "exception" from the point above also applies.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The first example in "Instead of" will execute
+ in a manner other than that which the developer desired (per indentation). Using code braces would have
+ prevented this "feature". The "explanation" and "exception" from the point above also applies.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S18" id="S18">4.4.3. Do not
- belabor/blow-up boolean expressions</a></h3>
+ <h3 class="SECT3"><a name="S18" id="S18">4.4.3. Do not belabor/blow-up boolean expressions</a></h3>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- structure->flag = (condition);</pre>
+ <pre class="PROGRAMLISTING">structure->flag = (condition);</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
- <p>if (condition) { structure->flag = 1; } else {
- structure->flag = 0; }</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
- former is readable and concise. The later is wordy and inefficient.
- Please assume that any developer new to the project has at least a
- "good" knowledge of C/C++. (Hope I do not offend by that last comment
- ... 8-)</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
+ <p>if (condition) { structure->flag = 1; } else { structure->flag = 0; }</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The former is readable and concise. The later is
+ wordy and inefficient. Please assume that any developer new to the project has at least a "good" knowledge of
+ C/C++. (Hope I do not offend by that last comment ... 8-)</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S19" id="S19">4.4.4. Use white space
- freely because it is free</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Make it readable. The notable exception to using white space
- freely is listed in the next guideline.</p>
+ <h3 class="SECT3"><a name="S19" id="S19">4.4.4. Use white space freely because it is free</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Make it readable. The notable exception to using white space freely is listed in the next guideline.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S20" id="S20">4.4.5. Don't use white space
- around structure operators</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>- structure pointer operator ( "->" ) - member operator ( "." )
- - functions and parentheses</p>
- <p>It is a general coding practice to put pointers, references, and
- function parentheses next to names. With spaces, the connection
- between the object and variable/function name is not as clear.</p>
+ <h3 class="SECT3"><a name="S20" id="S20">4.4.5. Don't use white space around structure operators</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>- structure pointer operator ( "->" ) - member operator ( "." ) - functions and parentheses</p>
+ <p>It is a general coding practice to put pointers, references, and function parentheses next to names. With
+ spaces, the connection between the object and variable/function name is not as clear.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span>
- a_struct -> a_member; a_struct . a_member; function_name ();</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span> a_struct -> a_member; a_struct .
+ a_member; function_name ();</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S21" id="S21">4.4.6. Make the last brace
- of a function stand out</a></h3>
+ <h3 class="SECT3"><a name="S21" id="S21">4.4.6. Make the last brace of a function stand out</a></h3>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
- <p>int function1( ... ) { ...code... return(ret_code); } int
- function2( ... ) { }</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> Use 1
- blank line before the closing brace and 2 lines afterward. This makes
- the end of function standout to the most casual viewer. Although
- function comments help separate functions, this is still a good
- coding practice. In fact, I follow these rules when using blocks in
- "for", "while", "do" loops, and long if {} statements too. After all
- whitespace is free!</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- developer-discretion on the number of blank lines. Enforced is the
- end of function comments.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
+ <p>int function1( ... ) { ...code... return(ret_code); } int function2( ... ) { }</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> Use 1 blank line before the closing brace and 2
+ lines afterward. This makes the end of function standout to the most casual viewer. Although function comments
+ help separate functions, this is still a good coding practice. In fact, I follow these rules when using blocks
+ in "for", "while", "do" loops, and long if {} statements too. After all whitespace is free!</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> developer-discretion on the number of blank
+ lines. Enforced is the end of function comments.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S22" id="S22">4.4.7. Use 3 character
- indentions</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>If some use 8 character TABs and some use 3 character TABs, the
- code can look *very* ragged. So use 3 character indentions only. If
- you like to use TABs, pass your code through a filter such as "expand
- -t3" before checking in your code.</p>
+ <h3 class="SECT3"><a name="S22" id="S22">4.4.7. Use 3 character indentions</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>If some use 8 character TABs and some use 3 character TABs, the code can look *very* ragged. So use 3
+ character indentions only. If you like to use TABs, pass your code through a filter such as "expand -t3" before
+ checking in your code.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- static const char * const url_code_map[256] =
+ <pre class="PROGRAMLISTING">static const char * const url_code_map[256] =
{
NULL, ...
};
<div class="SECT2">
<h2 class="SECT2"><a name="S23" id="S23">4.5. Initializing</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S24" id="S24">4.5.1. Initialize all
- variables</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Do not assume that the variables declared will not be used until
- after they have been assigned a value somewhere else in the code.
- Remove the chance of accidentally using an unassigned variable.</p>
+ <h3 class="SECT3"><a name="S24" id="S24">4.5.1. Initialize all variables</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Do not assume that the variables declared will not be used until after they have been assigned a value
+ somewhere else in the code. Remove the chance of accidentally using an unassigned variable.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It is
- much easier to debug a SIGSEGV if the message says you are trying to
- access memory address 00000000 and not 129FA012; or array_ptr[20]
- causes a SIGSEV vs. array_ptr[0].</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- developer-discretion if and only if the variable is assigned a value
- "shortly after" declaration.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It is much easier to debug a SIGSEGV if the
+ message says you are trying to access memory address 00000000 and not 129FA012; or array_ptr[20] causes a
+ SIGSEV vs. array_ptr[0].</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> developer-discretion if and only if the
+ variable is assigned a value "shortly after" declaration.</p>
</div>
</div>
<div class="SECT2">
<h2 class="SECT2"><a name="S25" id="S25">4.6. Functions</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S26" id="S26">4.6.1. Name functions that
- return a boolean as a question.</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Value should be phrased as a question that would logically be
- answered as a true or false statement</p>
+ <h3 class="SECT3"><a name="S26" id="S26">4.6.1. Name functions that return a boolean as a question.</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Value should be phrased as a question that would logically be answered as a true or false statement</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S27" id="S27">4.6.2. Always specify a
- return type for a function.</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>The default return for a function is an int. To avoid ambiguity,
- create a return for a function when the return has a purpose, and
- create a void return type if the function does not need to return
- anything.</p>
+ <h3 class="SECT3"><a name="S27" id="S27">4.6.2. Always specify a return type for a function.</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>The default return for a function is an int. To avoid ambiguity, create a return for a function when the
+ return has a purpose, and create a void return type if the function does not need to return anything.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S28" id="S28">4.6.3. Minimize function
- calls when iterating by using variables</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>It is easy to write the following code, and a clear argument can
- be made that the code is easy to understand:</p>
+ <h3 class="SECT3"><a name="S28" id="S28">4.6.3. Minimize function calls when iterating by using
+ variables</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>It is easy to write the following code, and a clear argument can be made that the code is easy to
+ understand:</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- for (size_t cnt = 0; cnt < block_list_length(); cnt++)
+ <pre class="PROGRAMLISTING">for (size_t cnt = 0; cnt < block_list_length(); cnt++)
{
....
}</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span>
- Unfortunately, this makes a function call for each and every
- iteration. This increases the overhead in the program, because the
- compiler has to look up the function each time, call it, and return a
- value. Depending on what occurs in the block_list_length() call, it
- might even be creating and destroying structures with each iteration,
- even though in each case it is comparing "cnt" to the same value,
- over and over. Remember too - even a call to block_list_length() is a
- function call, with the same overhead.</p>
- <p>Instead of using a function call during the iterations, assign the
- value to a variable, and evaluate using the variable.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> Unfortunately, this makes a function call for
+ each and every iteration. This increases the overhead in the program, because the compiler has to look up the
+ function each time, call it, and return a value. Depending on what occurs in the block_list_length() call, it
+ might even be creating and destroying structures with each iteration, even though in each case it is comparing
+ "cnt" to the same value, over and over. Remember too - even a call to block_list_length() is a function call,
+ with the same overhead.</p>
+ <p>Instead of using a function call during the iterations, assign the value to a variable, and evaluate using
+ the variable.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span>
- if the value of block_list_length() *may* change or could
- *potentially* change, then you must code the function call in the
- for/while loop.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span> if the value of block_list_length() *may*
+ change or could *potentially* change, then you must code the function call in the for/while loop.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S29" id="S29">4.6.4. Pass and Return by
- Const Reference</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>This allows a developer to define a const pointer and call your
- function. If your function does not have the const keyword, we may
- not be able to use your function. Consider strcmp, if it were defined
- as: extern int strcmp(char *s1, char *s2);</p>
- <p>I could then not use it to compare argv's in main: int main(int
- argc, const char *argv[]) { strcmp(argv[0], "privoxy"); }</p>
- <p>Both these pointers are *const*! If the c runtime library
- maintainers do it, we should too.</p>
+ <h3 class="SECT3"><a name="S29" id="S29">4.6.4. Pass and Return by Const Reference</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>This allows a developer to define a const pointer and call your function. If your function does not have the
+ const keyword, we may not be able to use your function. Consider strcmp, if it were defined as: extern int
+ strcmp(char *s1, char *s2);</p>
+ <p>I could then not use it to compare argv's in main: int main(int argc, const char *argv[]) { strcmp(argv[0],
+ "privoxy"); }</p>
+ <p>Both these pointers are *const*! If the c runtime library maintainers do it, we should too.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S30" id="S30">4.6.5. Pass and Return by
- Value</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Most structures cannot fit onto a normal stack entry (i.e. they
- are not 4 bytes or less). Aka, a function declaration like: int
- load_aclfile(struct client_state csp)</p>
- <p>would not work. So, to be consistent, we should declare all
- prototypes with "pass by value": int load_aclfile(struct client_state
- *csp)</p>
+ <h3 class="SECT3"><a name="S30" id="S30">4.6.5. Pass and Return by Value</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Most structures cannot fit onto a normal stack entry (i.e. they are not 4 bytes or less). Aka, a function
+ declaration like: int load_aclfile(struct client_state csp)</p>
+ <p>would not work. So, to be consistent, we should declare all prototypes with "pass by value": int
+ load_aclfile(struct client_state *csp)</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S31" id="S31">4.6.6. Names of include
- files</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Your include statements should contain the file name without a
- path. The path should be listed in the Makefile, using -I as
- processor directive to search the indicated paths. An exception to
- this would be for some proprietary software that utilizes a partial
- path to distinguish their header files from system or other header
+ <h3 class="SECT3"><a name="S31" id="S31">4.6.6. Names of include files</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Your include statements should contain the file name without a path. The path should be listed in the
+ Makefile, using -I as processor directive to search the indicated paths. An exception to this would be for some
+ proprietary software that utilizes a partial path to distinguish their header files from system or other header
files.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- #include <iostream.h> /* This is not a local include */
+ <pre class="PROGRAMLISTING">#include <iostream.h> /* This is not a local include */
#include "config.h" /* This IS a local include */</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Exception:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exception:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /* This is not a local include, but requires a path element. */
+ <pre class="PROGRAMLISTING">/* This is not a local include, but requires a path element. */
#include <sys/fileName.h></pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span>
- Please! do not add "-I." to the Makefile without a _very_ good
- reason. This duplicates the #include "file.h" behavior.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> Please! do not add "-I." to the Makefile without
+ a _very_ good reason. This duplicates the #include "file.h" behavior.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S32" id="S32">4.6.7. Provide multiple
- inclusion protection</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Prevents compiler and linker errors resulting from redefinition of
- items.</p>
- <p>Wrap each header file with the following syntax to prevent
- multiple inclusions of the file. Of course, replace PROJECT_H with
- your file name, with "." Changed to "_", and make it uppercase.</p>
+ <h3 class="SECT3"><a name="S32" id="S32">4.6.7. Provide multiple inclusion protection</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Prevents compiler and linker errors resulting from redefinition of items.</p>
+ <p>Wrap each header file with the following syntax to prevent multiple inclusions of the file. Of course,
+ replace PROJECT_H with your file name, with "." Changed to "_", and make it uppercase.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S33" id="S33">4.6.8. Use `extern "C"` when
- appropriate</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>If our headers are included from C++, they must declare our
- functions as `extern "C"`. This has no cost in C, but increases the
- potential re-usability of our code.</p>
+ <h3 class="SECT3"><a name="S33" id="S33">4.6.8. Use `extern "C"` when appropriate</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>If our headers are included from C++, they must declare our functions as `extern "C"`. This has no cost in
+ C, but increases the potential re-usability of our code.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S34" id="S34">4.6.9. Where Possible, Use
- Forward Struct Declaration Instead of Includes</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Useful in headers that include pointers to other struct's.
- Modifications to excess header files may cause needless compiles.</p>
+ <h3 class="SECT3"><a name="S34" id="S34">4.6.9. Where Possible, Use Forward Struct Declaration Instead of
+ Includes</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Useful in headers that include pointers to other struct's. Modifications to excess header files may cause
+ needless compiles.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /*********************************************************************
+ <pre class="PROGRAMLISTING">/*********************************************************************
* We're avoiding an include statement here!
*********************************************************************/
struct file_list;
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
- declare "file_list xyz;" (without the pointer), then including the
- proper header file is necessary. If you only want to prototype a
- pointer, however, the header file is unnecessary.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> Use
- with discretion.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you declare "file_list xyz;" (without the
+ pointer), then including the proper header file is necessary. If you only want to prototype a pointer, however,
+ the header file is unnecessary.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> Use with discretion.</p>
</div>
</div>
<div class="SECT2">
- <h2 class="SECT2"><a name="S35" id="S35">4.7. General Coding
- Practices</a></h2>
+ <h2 class="SECT2"><a name="S35" id="S35">4.7. General Coding Practices</a></h2>
<div class="SECT3">
- <h3 class="SECT3"><a name="S36" id="S36">4.7.1. Turn on
- warnings</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation</i></span></p>
- <p>Compiler warnings are meant to help you find bugs. You should turn
- on as many as possible. With GCC, the switch is "-Wall". Try and fix
- as many warnings as possible.</p>
+ <h3 class="SECT3"><a name="S36" id="S36">4.7.1. Turn on warnings</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation</i></span></p>
+ <p>Compiler warnings are meant to help you find bugs. You should turn on as many as possible. With GCC, the
+ switch is "-Wall". Try and fix as many warnings as possible.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S37" id="S37">4.7.2. Provide a default
- case for all switch statements</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>What you think is guaranteed is never really guaranteed. The value
- that you don't think you need to check is the one that someday will
- be passed. So, to protect yourself from the unknown, always have a
- default step in a switch statement.</p>
+ <h3 class="SECT3"><a name="S37" id="S37">4.7.2. Provide a default case for all switch statements</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>What you think is guaranteed is never really guaranteed. The value that you don't think you need to check is
+ the one that someday will be passed. So, to protect yourself from the unknown, always have a default step in a
+ switch statement.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
- already have a default condition, you are obviously exempt from this
- point. Of note, most of the WIN32 code calls `DefWindowProc' after
- the switch statement. This API call *should* be included in a default
- statement.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Another
- Note:</i></span> This is not so much a readability issue as a robust
- programming issue. The "anomaly code goes here" may be no more than a
- print to the STDERR stream (as in load_config). Or it may really be
- an abort condition.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- Programmer discretion is advised.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you already have a default condition, you are
+ obviously exempt from this point. Of note, most of the WIN32 code calls `DefWindowProc' after the switch
+ statement. This API call *should* be included in a default statement.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Another Note:</i></span> This is not so much a readability issue
+ as a robust programming issue. The "anomaly code goes here" may be no more than a print to the STDERR stream
+ (as in load_config). Or it may really be an abort condition.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> Programmer discretion is advised.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S38" id="S38">4.7.3. Try to avoid falling
- through cases in a switch statement.</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>In general, you will want to have a 'break' statement within each
- 'case' of a switch statement. This allows for the code to be more
- readable and understandable, and furthermore can prevent unwanted
- surprises if someone else later gets creative and moves the code
- around.</p>
- <p>The language allows you to plan the fall through from one case
- statement to another simply by omitting the break statement within
- the case statement. This feature does have benefits, but should only
- be used in rare cases. In general, use a break statement for each
- case statement.</p>
- <p>If you choose to allow fall through, you should comment both the
- fact of the fall through and reason why you felt it was
- necessary.</p>
+ <h3 class="SECT3"><a name="S38" id="S38">4.7.3. Try to avoid falling through cases in a switch
+ statement.</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>In general, you will want to have a 'break' statement within each 'case' of a switch statement. This allows
+ for the code to be more readable and understandable, and furthermore can prevent unwanted surprises if someone
+ else later gets creative and moves the code around.</p>
+ <p>The language allows you to plan the fall through from one case statement to another simply by omitting the
+ break statement within the case statement. This feature does have benefits, but should only be used in rare
+ cases. In general, use a break statement for each case statement.</p>
+ <p>If you choose to allow fall through, you should comment both the fact of the fall through and reason why you
+ felt it was necessary.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S40" id="S40">4.7.4. Don't mix size_t and
- other types</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>The type of size_t varies across platforms. Do not make
- assumptions about whether it is signed or unsigned, or about how long
- it is. Do not compare a size_t against another variable of a
- different type (or even against a constant) without casting one of
- the values.</p>
+ <h3 class="SECT3"><a name="S40" id="S40">4.7.4. Don't mix size_t and other types</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>The type of size_t varies across platforms. Do not make assumptions about whether it is signed or unsigned,
+ or about how long it is. Do not compare a size_t against another variable of a different type (or even against
+ a constant) without casting one of the values.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S41" id="S41">4.7.5. Declare each variable
- and struct on its own line.</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>It can be tempting to declare a series of variables all on one
- line. Don't.</p>
+ <h3 class="SECT3"><a name="S41" id="S41">4.7.5. Declare each variable and struct on its own line.</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>It can be tempting to declare a series of variables all on one line. Don't.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Instead
- of:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span></p>
<p>long a, b, c;</p>
- <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span>
- - there is more room for comments on the individual variables -
- easier to add new variables without messing up the original ones -
- when searching on a variable to find its type, there is less clutter
- to "visually" eliminate</p>
- <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span>
- when you want to declare a bunch of loop variables or other trivial
- variables; feel free to declare them on one line. You should,
- although, provide a good comment on their functions.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- developer-discretion.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span> - there is more room for comments on the
+ individual variables - easier to add new variables without messing up the original ones - when searching on a
+ variable to find its type, there is less clutter to "visually" eliminate</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span> when you want to declare a bunch of loop
+ variables or other trivial variables; feel free to declare them on one line. You should, although, provide a
+ good comment on their functions.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> developer-discretion.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S42" id="S42">4.7.6. Use malloc/zalloc
- sparingly</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>Create a local struct (on the stack) if the variable will live and
- die within the context of one function call.</p>
- <p>Only "malloc" a struct (on the heap) if the variable's life will
- extend beyond the context of one function call.</p>
+ <h3 class="SECT3"><a name="S42" id="S42">4.7.6. Use malloc/zalloc sparingly</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>Create a local struct (on the stack) if the variable will live and die within the context of one function
+ call.</p>
+ <p>Only "malloc" a struct (on the heap) if the variable's life will extend beyond the context of one function
+ call.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- If a function creates a struct and stores a pointer to it in a
+ <pre class="PROGRAMLISTING">If a function creates a struct and stores a pointer to it in a
list, then it should definitely be allocated via `malloc'.</pre>
</td>
</tr>
</table>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S43" id="S43">4.7.7. The Programmer Who
- Uses 'malloc' is Responsible for Ensuring 'free'</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>If you have to "malloc" an instance, you are responsible for
- insuring that the instance is `free'd, even if the deallocation event
- falls within some other programmer's code. You are also responsible
- for ensuring that deletion is timely (i.e. not too soon, not too
- late). This is known as "low-coupling" and is a "good thing (tm)".
- You may need to offer a free/unload/destructor type function to
- accommodate this.</p>
+ <h3 class="SECT3"><a name="S43" id="S43">4.7.7. The Programmer Who Uses 'malloc' is Responsible for Ensuring
+ 'free'</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>If you have to "malloc" an instance, you are responsible for insuring that the instance is `free'd, even if
+ the deallocation event falls within some other programmer's code. You are also responsible for ensuring that
+ deletion is timely (i.e. not too soon, not too late). This is known as "low-coupling" and is a "good thing
+ (tm)". You may need to offer a free/unload/destructor type function to accommodate this.</p>
<p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- int load_re_filterfile(struct client_state *csp) { ... }
+ <pre class="PROGRAMLISTING">int load_re_filterfile(struct client_state *csp) { ... }
static void unload_re_filterfile(void *f) { ... }</pre>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Exceptions:</i></span></p>
- <p>The developer cannot be expected to provide `free'ing functions
- for C run-time library functions ... such as `strdup'.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
- developer-discretion. The "main" use of this standard is for
- allocating and freeing data structures (complex or nested).</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span></p>
+ <p>The developer cannot be expected to provide `free'ing functions for C run-time library functions ... such as
+ `strdup'.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> developer-discretion. The "main" use of this
+ standard is for allocating and freeing data structures (complex or nested).</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S44" id="S44">4.7.8. Add loaders to the
- `file_list' structure and in order</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>I have ordered all of the "blocker" file code to be in alpha
- order. It is easier to add/read new blockers when you expect a
- certain order.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It may
- appear that the alpha order is broken in places by POPUP tests coming
- before PCRS tests. But since POPUPs can also be referred to as
- KILLPOPUPs, it is clear that it should come first.</p>
+ <h3 class="SECT3"><a name="S44" id="S44">4.7.8. Add loaders to the `file_list' structure and in order</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>I have ordered all of the "blocker" file code to be in alpha order. It is easier to add/read new blockers
+ when you expect a certain order.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It may appear that the alpha order is broken in
+ places by POPUP tests coming before PCRS tests. But since POPUPs can also be referred to as KILLPOPUPs, it is
+ clear that it should come first.</p>
</div>
<div class="SECT3">
- <h3 class="SECT3"><a name="S45" id="S45">4.7.9. "Uncertain" new code
- and/or changes to existing code, use XXX</a></h3>
- <p><span class="emphasis"><i class=
- "EMPHASIS">Explanation:</i></span></p>
- <p>If you have enough confidence in new code or confidence in your
- changes, but are not *quite* sure of the repercussions, add this:</p>
- <p>/* XXX: this code has a logic error on platform XYZ, * attempting
- to fix */ #ifdef PLATFORM ...changed code here... #endif</p>
+ <h3 class="SECT3"><a name="S45" id="S45">4.7.9. "Uncertain" new code and/or changes to existing code, use
+ XXX</a></h3>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span></p>
+ <p>If you have enough confidence in new code or confidence in your changes, but are not *quite* sure of the
+ repercussions, add this:</p>
+ <p>/* XXX: this code has a logic error on platform XYZ, * attempting to fix */ #ifdef PLATFORM ...changed code
+ here... #endif</p>
<p>or:</p>
- <p>/* XXX: I think the original author really meant this... */
- ...changed code here...</p>
+ <p>/* XXX: I think the original author really meant this... */ ...changed code here...</p>
<p>or:</p>
- <p>/* XXX: new code that *may* break something else... */ ...new code
- here...</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
- make it clear that this may or may not be a "good thing (tm)", it
- will be easier to identify and include in the project (or conversely
- exclude from the project).</p>
+ <p>/* XXX: new code that *may* break something else... */ ...new code here...</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you make it clear that this may or may not be
+ a "good thing (tm)", it will be easier to identify and include in the project (or conversely exclude from the
+ project).</p>
</div>
</div>
<div class="SECT2">
- <h2 class="SECT2"><a name="S46" id="S46">4.8. Addendum: Template for
- files and function comment blocks:</a></h2>
- <p><span class="emphasis"><i class="EMPHASIS">Example for file
- comments:</i></span></p>
+ <h2 class="SECT2"><a name="S46" id="S46">4.8. Addendum: Template for files and function comment blocks:</a></h2>
+ <p><span class="emphasis"><i class="EMPHASIS">Example for file comments:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- const char FILENAME_rcs[] = "$I<!-- Break CVS Substitution -->d$";
+ <pre class="PROGRAMLISTING">const char FILENAME_rcs[] = "$I<!-- Break CVS Substitution -->d$";
/*********************************************************************
*
* File : $S<!-- Break CVS Substitution -->ource$
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> This
- declares the rcs variables that should be added to the "show-version"
- page. If this is a brand new creation by you, you are free to change
- the "Copyright" section to represent the rights you wish to
- maintain.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
- formfeed character that is present right after the comment flower box
- is handy for (X|GNU)Emacs users to skip the verbiage and get to the
- heart of the code (via `forward-page' and `backward-page'). Please
- include it if you can.</p>
- <p><span class="emphasis"><i class="EMPHASIS">Example for file header
- comments:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> This declares the rcs variables that should be
+ added to the "show-version" page. If this is a brand new creation by you, you are free to change the "Copyright"
+ section to represent the rights you wish to maintain.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The formfeed character that is present right after
+ the comment flower box is handy for (X|GNU)Emacs users to skip the verbiage and get to the heart of the code (via
+ `forward-page' and `backward-page'). Please include it if you can.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Example for file header comments:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Example for function
- comments:</i></span></p>
+ <p><span class="emphasis"><i class="EMPHASIS">Example for function comments:</i></span></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
- /*********************************************************************
+ <pre class="PROGRAMLISTING">/*********************************************************************
*
* Function : FUNCTION_NAME
*
</td>
</tr>
</table>
- <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If we
- all follow this practice, we should be able to parse our code to create
- a "self-documenting" web page.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If we all follow this practice, we should be able
+ to parse our code to create a "self-documenting" web page.</p>
</div>
</div>
<div class="NAVFOOTER">
<hr align="left" width="100%">
- <table summary="Footer navigation table" width="100%" border="0"
- cellpadding="0" cellspacing="0">
+ <table summary="Footer navigation table" width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
- <td width="33%" align="left" valign="top"><a href=
- "documentation.html" accesskey="P">Prev</a></td>
- <td width="34%" align="center" valign="top"><a href="index.html"
- accesskey="H">Home</a></td>
- <td width="33%" align="right" valign="top"><a href="testing.html"
- accesskey="N">Next</a></td>
+ <td width="33%" align="left" valign="top"><a href="documentation.html" accesskey="P">Prev</a></td>
+ <td width="34%" align="center" valign="top"><a href="index.html" accesskey="H">Home</a></td>
+ <td width="33%" align="right" valign="top"><a href="testing.html" accesskey="N">Next</a></td>
</tr>
<tr>
- <td width="33%" align="left" valign="top">Documentation
- Guidelines</td>
+ <td width="33%" align="left" valign="top">Documentation Guidelines</td>
<td width="34%" align="center" valign="top"> </td>
<td width="33%" align="right" valign="top">Testing Guidelines</td>
</tr>
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