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.
sys/time.h — time types
header shall define the timeval
which shall include at least the following members:
time_t tv_sec Seconds.
suseconds_t tv_usec Microseconds.
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.
header shall define the time_t
types as described in <sys/types.h>
header shall define the fd_set
described in <sys/select.h>
header shall define the following symbolic
constants for the which
argument of getitimer
- 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.
header shall define the following as described in
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 );
Inclusion of the <sys/time.h>
header may make visible all symbols
from the <sys/select.h>
The following sections are informative.
The System Interfaces volume of POSIX.1‐2008, futimens()
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
7, Copyright (C) 2013 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013
Technical Corrigendum 1 applied.) In the event of any discrepancy between this
version and the original IEEE and The Open Group Standard, the original IEEE
and The Open Group Standard is the referee document. The original Standard can
be obtained online at http://www.unix.org/online.html .
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