sys/time.h - time types
[XSI] #include <sys/time.h>
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() and setitimer():
- Decrements in real time.
- Decrements in process virtual time.
- 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.[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 );
Inclusion of the <sys/time.h> header may make visible all symbols from the <sys/select.h> header.
XSH futimens, getitimer, gettimeofday, pselect
First released in Issue 4, Version 2.
The type of tv_usec is changed from long to suseconds_t.
The restrict keyword is added to the prototypes for gettimeofday(), select(), and setitimer().
The note is added that inclusion of this header may also make symbols visible from <sys/select.h>.
The utimes() function is marked LEGACY.
This reference page is clarified with respect to macros and symbolic constants.
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