SYS_TIME.H(7) Miscellaneous Information Manual SYS_TIME.H(7)

NAME

sys/time.h — time types

SYNOPSIS

[XSI]
#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.

[OB] 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>.

[OB] The <sys/time.h> header shall define the following symbolic constants for the which argument of getitimer(3) and setitimer(3):

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(3) FD_ISSET(3) FD_SET(3) FD_ZERO(3) FD_SETSIZE

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

[OB]
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.