2004-11-03 13:51:07 +00:00
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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2007-06-20 22:33:04 +00:00
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.TH "<sys/time.h>" 0P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.\" <sys/time.h>
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.SH NAME
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sys/time.h \- time types
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.SH SYNOPSIS
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.LP
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\fB#include <sys/time.h> \fP
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.SH DESCRIPTION
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.LP
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The \fI<sys/time.h>\fP header shall define the \fBtimeval\fP structure
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that includes at least the following members:
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.sp
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.RS
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.nf
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\fBtime_t tv_sec \fP Seconds. \fB
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suseconds_t tv_usec \fP Microseconds. \fB
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\fP
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.fi
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.RE
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.LP
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The \fI<sys/time.h>\fP header shall define the \fBitimerval\fP structure
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that includes at least the following
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members:
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.sp
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.RS
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.nf
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\fBstruct timeval it_interval\fP Timer interval. \fB
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struct timeval it_value \fP Current value. \fB
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\fP
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.fi
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.RE
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.LP
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The \fBtime_t\fP and \fBsuseconds_t\fP types shall be defined as described
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in \fI<sys/types.h>\fP .
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.LP
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The \fBfd_set\fP type shall be defined as described in \fI<sys/select.h>\fP
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\&.
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.LP
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The \fI<sys/time.h>\fP header shall define the following values for
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the \fIwhich\fP argument of \fIgetitimer\fP() and \fIsetitimer\fP():
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.TP 7
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ITIMER_REAL
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Decrements in real time.
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.TP 7
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ITIMER_VIRTUAL
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Decrements in process virtual time.
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.TP 7
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ITIMER_PROF
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Decrements both in process virtual time and when the system is running
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on behalf of the process.
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.sp
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.LP
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The following shall be defined as described in \fI<sys/select.h>\fP
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: \fIFD_CLR\fP() \fIFD_ISSET\fP() \fIFD_SET\fP() \fIFD_ZERO\fP() FD_SETSIZE
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.LP
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The following shall be declared as functions and may also be defined
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as macros. Function prototypes shall be provided.
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.sp
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.RS
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.nf
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\fBint getitimer(int, struct itimerval *);
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int gettimeofday(struct timeval *restrict, void *restrict);
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int select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
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struct timeval *restrict);
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int setitimer(int, const struct itimerval *restrict,
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struct itimerval *restrict);
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int utimes(const char *, const struct timeval [2]); (\fP\fBLEGACY\fP \fB)
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\fP
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.fi
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.RE
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.LP
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Inclusion of the \fI<sys/time.h>\fP header may make visible all symbols
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from the \fI<sys/select.h>\fP header.
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.LP
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\fIThe following sections are informative.\fP
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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2007-09-20 06:36:16 +00:00
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\fI<sys/select.h>\fP, \fI<sys/types.h>\fP, the System Interfaces
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2004-11-03 13:51:07 +00:00
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volume of IEEE\ Std\ 1003.1-2001, \fIgetitimer\fP(), \fIgettimeofday\fP(),
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\fIselect\fP(), \fIsetitimer\fP()
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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