sys_time.h (0p)

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.
 

NAME

sys/time.h — time types

SYNOPSIS

#include <sys/time.h>

DESCRIPTION

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.

SEE ALSO

<sys_select.h>, <sys_types.h>
The System Interfaces volume of POSIX.1‐2008, futimens(), getitimer(), gettimeofday(), pselect()

Information

Source
POSIX
OS/version
IEEE/The Open Group
Source updated
January 1, 2013
Page created
March 3, 2018
Page generated
March 4, 2018