glibc/manual/examples/select.c

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/*@group*/
#include <errno.h>
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#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
/*@end group*/
/*@group*/
int
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input_timeout (int filedes, unsigned int seconds)
{
fd_set set;
struct timeval timeout;
/*@end group*/
/* Initialize the file descriptor set. */
FD_ZERO (&set);
FD_SET (filedes, &set);
/* Initialize the timeout data structure. */
timeout.tv_sec = seconds;
timeout.tv_usec = 0;
/*@group*/
/* @code{select} returns 0 if timeout, 1 if input available, -1 if error. */
return TEMP_FAILURE_RETRY (select (FD_SETSIZE,
&set, NULL, NULL,
&timeout));
}
/*@end group*/
/*@group*/
int
main (void)
{
fprintf (stderr, "select returned %d.\n",
input_timeout (STDIN_FILENO, 5));
return 0;
}
/*@end group*/