sys_time.h(0p)

Usage

#include <sys/time.h>

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

Overview

The <sys/time.h> header shall define the timeval structure, which shall include at least the following members:

time_t         tv_sec      Seconds.
suseconds_t    tv_usec     Microseconds.

The <sys/time.h> header shall define the itimerval structure, which shall include at least the following members:

struct timeval it_interval Timer interval.
struct timeval it_value    Current value.

The <sys/time.h> header shall define the time_t and suseconds_t types as described in <sys/types.h>.

The <sys/time.h> header shall define the fd_set type as described in <sys/select.h>.

The <sys/time.h> header shall define the following symbolic constants for the which argument of getitimer() and setitimer():

ITIMER_REAL: Decrements in real time.

ITIMER_VIRTUAL: Decrements in process virtual time.

ITIMER_PROF: Decrements both in process virtual time and when the system is running on behalf of the process.

The <sys/time.h> header shall define the following as described in <sys/select.h>: FD_CLR() FD_ISSET() FD_SET() FD_ZERO() FD_SETSIZE

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

int   getitimer(int, struct itimerval *);
int   gettimeofday(struct timeval *restrict, void *restrict);
int   setitimer(int, const struct itimerval *restrict,
          struct itimerval *restrict);
int   select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
          struct timeval *restrict);
int   utimes(const char *, const struct timeval [2]);

Inclusion of the <sys/time.h> header may make visible all symbols from the <sys/select.h> header.

The following sections are informative.

Application usage

None.

Rationale

None.

Future directions

None.