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Standard C Library Functionsclock(3C)


NAME

 clock - report CPU time used

SYNOPSIS

 
#include <time.h>
clock_t clock(void);

DESCRIPTION

 

The clock() function returns the amount of CPU time (in microseconds) used since the first call to clock() in the calling process. The time reported is the sum of the user and system times of the calling process and its terminated child processes for which it has executed the wait(2) function, the pclose(3C) function, or the system(3C) function.

RETURN VALUES

 

Dividing the value returned by clock() by the constant CLOCKS_PER_SEC, defined in the <time.h> header, will give the time in seconds. If the process time used is not available or cannot be represented, clock returns the value (clock_t) -1.

USAGE

 

The value returned by clock() is defined in microseconds for compatibility with systems that have CPU clocks with much higher resolution. Because of this, the value returned will wrap around after accumulating only 2147 seconds of CPU time (about 36 minutes).

ATTRIBUTES

 

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelMT-Safe

SEE ALSO

 

times(2), wait(2), popen(3C), system(3C), attributes(5)


SunOS 5.9Go To TopLast Changed 29 Dec 1996

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.