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| <h4 class="subsection">21.3.2 Processor Time Inquiry</h4> |
| |
| <p>The <code>times</code> function returns information about a process' |
| consumption of processor time in a <code>struct tms</code><!-- /@w --> object, in |
| addition to the process' CPU time. See <a href="Time-Basics.html#Time-Basics">Time Basics</a>. You should |
| include the header file <samp><span class="file">sys/times.h</span></samp> to use this facility. |
| <a name="index-processor-time-2611"></a><a name="index-CPU-time-2612"></a><a name="index-sys_002ftimes_002eh-2613"></a> |
| <!-- sys/times.h --> |
| <!-- POSIX.1 --> |
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| <div class="defun"> |
| — Data Type: <b>struct tms</b><var><a name="index-struct-tms-2614"></a></var><br> |
| <blockquote><p>The <code>tms</code> structure is used to return information about process |
| times. It contains at least the following members: |
| |
| <dl> |
| <dt><code>clock_t tms_utime</code><dd>This is the total processor time the calling process has used in |
| executing the instructions of its program. |
| |
| <br><dt><code>clock_t tms_stime</code><dd>This is the processor time the system has used on behalf of the calling |
| process. |
| |
| <br><dt><code>clock_t tms_cutime</code><dd>This is the sum of the <code>tms_utime</code> values and the <code>tms_cutime</code> |
| values of all terminated child processes of the calling process, whose |
| status has been reported to the parent process by <code>wait</code> or |
| <code>waitpid</code>; see <a href="Process-Completion.html#Process-Completion">Process Completion</a>. In other words, it |
| represents the total processor time used in executing the instructions |
| of all the terminated child processes of the calling process, excluding |
| child processes which have not yet been reported by <code>wait</code> or |
| <code>waitpid</code>. |
| <a name="index-child-process-2615"></a> |
| <br><dt><code>clock_t tms_cstime</code><dd>This is similar to <code>tms_cutime</code>, but represents the total processor |
| time system has used on behalf of all the terminated child processes |
| of the calling process. |
| </dl> |
| |
| <p>All of the times are given in numbers of clock ticks. Unlike CPU time, |
| these are the actual amounts of time; not relative to any event. |
| See <a href="Creating-a-Process.html#Creating-a-Process">Creating a Process</a>. |
| </p></blockquote></div> |
| |
| <!-- sys/times.h --> |
| <!-- POSIX.1 --> |
| <div class="defun"> |
| — Function: clock_t <b>times</b> (<var>struct tms *buffer</var>)<var><a name="index-times-2616"></a></var><br> |
| <blockquote><p>The <code>times</code> function stores the processor time information for |
| the calling process in <var>buffer</var>. |
| |
| <p>The return value is the calling process' CPU time (the same value you |
| get from <code>clock()</code>. <code>times</code> returns <code>(clock_t)(-1)</code> to |
| indicate failure. |
| </p></blockquote></div> |
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| <p><strong>Portability Note:</strong> The <code>clock</code> function described in |
| <a href="CPU-Time.html#CPU-Time">CPU Time</a> is specified by the ISO C<!-- /@w --> standard. The |
| <code>times</code> function is a feature of POSIX.1. In the GNU system, the |
| CPU time is defined to be equivalent to the sum of the <code>tms_utime</code> |
| and <code>tms_stime</code> fields returned by <code>times</code>. |
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