x-coding3.html

vxworks相关论文

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84532"> </a>Compose multi-line comments in declarations and at the end of code statements with one or more one-line comments, opened and closed on the same line. For example:</li></ul>
</p>
<dl class="margin">

<dd><pre class="Code2"><b><a name="84533">int foo 
    ( 
    int&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/* this is the correct format for a */ 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/* multiline comment in a declaration */ 
    BOOL&nbsp;&nbsp;&nbsp;&nbsp;b&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/* standard comment at the end of a line */ 
    )</a></b><dd>
 
<b><a name="84534">    { 
    day = night;&nbsp;&nbsp;&nbsp;/* when necessary, a comment about a line */ 
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;/* of code can be done this way */ 
    }</a></b></pre>
</dl>

</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H3"><i><a name="84537">I.3.5  &nbsp;&nbsp;C Naming Conventions</a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="84539"> </a>The following conventions define the standards for naming modules, routines, variables, constants, macros, types, and structure and union members. The purpose of these conventions is uniformity and readability of code.</p>
</dl>

<dl class="margin">

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84540"> </a>When creating names, remember that the code is written only once, but read many times. Assign names that are meaningful and readable; avoid obscure abbreviations.</li></ul>
</p>
<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84542"> </a>Names of routines, variables, and structure and union members are composed of upper- and lowercase characters and no underbars. Capitalize each "word" except the first:</li></ul>
</p>
<dl class="margin">

<dd><div class="Indent"><a name="84543"> </a><b class="symbol_lc">aVariableName</b></div>
<br>
</dl>

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84544"> </a>Names of defined types (defined with <b class="keyword">typedef</b>), and constants and macros (defined with <b class="keyword">#define</b>), are all uppercase with underbars separating the words in the name:</li></ul>
</p>
<dl class="margin">

<dd><div class="Indent"><a name="84545"> </a><b class="symbol_UC">A_CONSTANT_VALUE</b> </div>
<br>
</dl>

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84546"> </a>Every module has a short prefix (two to five characters). The prefix is attached to the module name and all externally available routines, variables, constants, macros, and<b class="keyword"> typedefs</b>. (Names not available externally do not follow this convention.)<p class="table">
<table border="0" cellpadding="0" cellspacing="0">
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84549"> </a><b class="symbol_lc">fooLib.c</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84551"> </a>module name</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84553"> </a><b class="symbol_lc">fooObjFind</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84555"> </a>subroutine name</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84557"> </a><b class="symbol_lc">fooCount</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84559"> </a>variable name</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84561"> </a><b class="symbol_UC">FOO_MAX_COUNT</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84563"> </a>constant</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84565"> </a><b class="symbol_UC">FOO_NODE</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84567"> </a>type </p>

</td>


</tr>

<tr valign="middle">
<td colspan="20">

</td>
</tr>
</table>
</p>
</li></ul>
</p>
<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84568"> </a>Names of routines follow the <i class="emphasis">module</i>-<i class="emphasis">noun</i>-<i class="emphasis">verb</i> rule. Start the routine name with the module prefix, followed by the noun or object that the routine manipulates. Conclude the name with the verb or action the routine performs:<p class="table">
<table border="0" cellpadding="0" cellspacing="0">
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84571"> </a><b class="symbol_lc">fooObjFind</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84573"> </a>foo - object - find</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84575"> </a><b class="symbol_lc">sysNvRamGet</b> </p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84577"> </a>system - NVRAM - get</p>

</td>


</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84579"> </a><b class="symbol_lc">taskSwitchHookAdd </b></p>

</td>

<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="84581"> </a>task - switch hook - add</p>

</td>


</tr>

<tr valign="middle">
<td colspan="20">

</td>
</tr>
</table>
</p>
</li></ul>
</p>
<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84582"> </a>Every header file defines a preprocessor symbol that prevents the file from being included more than once. This symbol is formed from the header file name by prefixing <b class="symbol_UC">__INC</b> and removing the dot (<b class="operator">.</b>). For example, if the header file is called <b class="file">fooLib.h</b>, the <i class="emphasis">multiple inclusion guard symbol</i> is:</li></ul>
</p>
<dl class="margin">

<dd><div class="Indent"><a name="84583"> </a><b class="symbol_lc">__INCfooLibh </b></div>
<br>
</dl>

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84584"> </a>Pointer variable names have the prefix <i class="term">p</i> for each level of indirection. For example:</li></ul>
</p>
<dl class="margin">

<dd><pre class="Code2"><b><a name="84585">FOO_NODE *      pFooNode; 
FOO_NODE **     ppFooNode; 
FOO_NODE ***    pppFooNode;</a></b></pre>
</dl>

</dl>

</dl>

<font face="Helvetica, sans-serif" class="sans">
<h4 class="H3"><i><a name="84587">I.3.6  &nbsp;&nbsp;C Style</a></i></h4>
</font>
<dl class="margin">

<dl class="margin">

<dd><p class="Body"><a name="84589"> </a>The following conventions define additional standards of programming style:</p>
</dl>

<dl class="margin">

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84590"> </a><font face="Helvetica, sans-serif" size="-1" class="sans"><b class="hb">Comments:</b></font>&nbsp;&nbsp;Insufficiently commented code is unacceptable.</li></ul>
</p>
<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84591"> </a><font face="Helvetica, sans-serif" size="-1" class="sans"><b class="hb">Numeric Constants:</b></font>&nbsp;&nbsp;Use <b class="keyword">#define</b> to define meaningful names for constants. Do not use numeric constants in code or declarations (except for obvious uses of small constants like 0 and 1).</li></ul>
</p>
<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84592"> </a><font face="Helvetica, sans-serif" size="-1" class="sans"><b class="hb">Boolean Tests:</b></font>&nbsp;&nbsp;Do not test non-booleans as you test a boolean. For example, where <b class="symbol_lc">x</b> is an integer:<p class="table">

<table border="0" cellpadding="0" cellspacing="0">
<tr>
<td colspan="20">
<hr class="tablerule">
</td>
</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="85098"> </a>CORRECT:</p>

</td>
<td colspan=1 rowspan=1>
<pre class="CodeLeft"><b><a name="85100">if (x == 0)</a></b></pre>

</td>

</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="85102"> </a>INCORRECT:</p>

</td>
<td colspan=1 rowspan=1>
<pre class="CodeLeft"><b><a name="85104">if (! x)</a></b></pre>

</td>

</tr>

<tr>
<td colspan="20">
<hr class="tablerule">
</td>
</tr>
<tr valign="middle">
<td colspan="20">

</td>
</tr>
</table>
</p>
</li></ul>
</p>
<dl class="margin">

<dd><div class="Indent"><a name="84597"> </a>Similarly, do not test booleans as non-booleans. For example, where <b class="symbol_lc">libInstalled</b> is declared as <b class="symbol_UC">BOOL</b>:<p class="table">

<table border="0" cellpadding="0" cellspacing="0">
<tr>
<td colspan="20">
<hr class="tablerule">
</td>
</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="85111"> </a>CORRECT:</p>

</td>
<td colspan=1 rowspan=1>
<pre class="CodeLeft"><b><a name="85113">if (libInstalled)</a></b></pre>

</td>

</tr>
<tr valign="top">
<td colspan=1 rowspan=1>
<p class="BodyLeft"><a name="85115"> </a>INCORRECT:</p>

</td>
<td colspan=1 rowspan=1>
<pre class="CodeLeft"><b><a name="85117">if (libInstalled == TRUE)</a></b></pre>

</td>

</tr>

<tr>
<td colspan="20">
<hr class="tablerule">
</td>
</tr>
<tr valign="middle">
<td colspan="20">

</td>
</tr>
</table>
</p>
</div>
<br>
</dl>

<p class="listspace">
<ul class="Bullet" type="disc"><li><a name="84602"> </a><font face="Helvetica, sans-serif" size="-1" class="sans"><b class="hb">Private Interfaces:</b></font>&nbsp;&nbsp;Private interfaces are functions and data that are internal to an application or library and do not form part of the intended external user interface. Place private interfaces in a header file residing in a directory named <b class="file">private</b>. End the name of the header file with an uppercase <i class="term">P</i> (for <i class="term">private</i>). For example, the private function prototypes and data for the commonly used internal functions in the library <b class="library">blahLib</b> would be placed in the file <b class="file">private/private/blahLibP.h</b>. </li></ul>
</p>
<p class="listspace">