usleep

Name

usleep - suspend execution for microsecond intervals

Library

libc.lib

Synopsis

#include <unistd.h>

int usleep (useconds_t microseconds);

Return values

The usleep function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

Detailed description

The usleep function suspends execution of the calling process until either microseconds microseconds have elapsed or a signal is delivered to the process and its action is to invoke a signal-catching function or to terminate the process. System activity may lengthen the sleep by an indeterminate amount.

This function is implemented using nanosleep by pausing for microseconds microseconds or until a signal occurs. Consequently, in this implementation, sleeping has no effect on the state of process timers, and there is no special handling for SIGALRM.

Examples

#include<unistd.h>
#include<stdio.h>
 
int main()
{
 unsigned long t = 2; 
 int i;
  
 i = usleep(t);
 printf("Expected: 0 usleep returned: %d", i);
  
 return 0;
}

Output

Expected: 0 usleep returned: 0

Errors

The usleep function will fail if:

[`EINTR`]
	A signal was delivered to the process and its action was to invoke a signal-catching function.

Limitations

The signal related functionaities aren’t applicable to the symbian implementation as there is no support for signals from symbian.

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