mirror of https://github.com/mkerrisk/man-pages
104 lines
3.0 KiB
Plaintext
104 lines
3.0 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
|
|
.TH "<sys/time.h>" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
|
|
.\" <sys/time.h>
|
|
.SH NAME
|
|
sys/time.h \- time types
|
|
.SH SYNOPSIS
|
|
.LP
|
|
\fB#include <sys/time.h> \fP
|
|
.SH DESCRIPTION
|
|
.LP
|
|
The \fI<sys/time.h>\fP header shall define the \fBtimeval\fP structure
|
|
that includes at least the following members:
|
|
.sp
|
|
.RS
|
|
.nf
|
|
|
|
\fBtime_t tv_sec \fP Seconds. \fB
|
|
suseconds_t tv_usec \fP Microseconds. \fB
|
|
\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
The \fI<sys/time.h>\fP header shall define the \fBitimerval\fP structure
|
|
that includes at least the following
|
|
members:
|
|
.sp
|
|
.RS
|
|
.nf
|
|
|
|
\fBstruct timeval it_interval\fP Timer interval. \fB
|
|
struct timeval it_value \fP Current value. \fB
|
|
\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
The \fBtime_t\fP and \fBsuseconds_t\fP types shall be defined as described
|
|
in \fI<sys/types.h>\fP .
|
|
.LP
|
|
The \fBfd_set\fP type shall be defined as described in \fI<sys/select.h>\fP
|
|
\&.
|
|
.LP
|
|
The \fI<sys/time.h>\fP header shall define the following values for
|
|
the \fIwhich\fP argument of \fIgetitimer\fP() and \fIsetitimer\fP():
|
|
.TP 7
|
|
ITIMER_REAL
|
|
Decrements in real time.
|
|
.TP 7
|
|
ITIMER_VIRTUAL
|
|
Decrements in process virtual time.
|
|
.TP 7
|
|
ITIMER_PROF
|
|
Decrements both in process virtual time and when the system is running
|
|
on behalf of the process.
|
|
.sp
|
|
.LP
|
|
The following shall be defined as described in \fI<sys/select.h>\fP
|
|
: \fIFD_CLR\fP() \fIFD_ISSET\fP() \fIFD_SET\fP() \fIFD_ZERO\fP() FD_SETSIZE
|
|
.LP
|
|
The following shall be declared as functions and may also be defined
|
|
as macros. Function prototypes shall be provided.
|
|
.sp
|
|
.RS
|
|
.nf
|
|
|
|
\fBint getitimer(int, struct itimerval *);
|
|
int gettimeofday(struct timeval *restrict, void *restrict);
|
|
int select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
|
|
struct timeval *restrict);
|
|
int setitimer(int, const struct itimerval *restrict,
|
|
struct itimerval *restrict);
|
|
int utimes(const char *, const struct timeval [2]); (\fP\fBLEGACY\fP \fB)
|
|
\fP
|
|
.fi
|
|
.RE
|
|
.LP
|
|
Inclusion of the \fI<sys/time.h>\fP header may make visible all symbols
|
|
from the \fI<sys/select.h>\fP header.
|
|
.LP
|
|
\fIThe following sections are informative.\fP
|
|
.SH APPLICATION USAGE
|
|
.LP
|
|
None.
|
|
.SH RATIONALE
|
|
.LP
|
|
None.
|
|
.SH FUTURE DIRECTIONS
|
|
.LP
|
|
None.
|
|
.SH SEE ALSO
|
|
.LP
|
|
\fI<sys/select.h>\fP , \fI<sys/types.h>\fP , the System Interfaces
|
|
volume of IEEE\ Std\ 1003.1-2001, \fIgetitimer\fP(), \fIgettimeofday\fP(),
|
|
\fIselect\fP(), \fIsetitimer\fP()
|
|
.SH COPYRIGHT
|
|
Portions of this text are reprinted and reproduced in electronic form
|
|
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
|
|
-- Portable Operating System Interface (POSIX), The Open Group Base
|
|
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
|
|
Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html .
|