1sys_select.h(0P)           POSIX Programmer's Manual          sys_select.h(0P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

13       sys/select.h — select types
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SYNOPSIS

16       #include <sys/select.h>
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DESCRIPTION

19       The <sys/select.h> header shall define  the  timeval  structure,  which
20       shall include at least the following members:
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22           time_t         tv_sec      Seconds.
23           suseconds_t    tv_usec     Microseconds.
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25       The <sys/select.h> header shall define the time_t and suseconds_t types
26       as described in <sys/types.h>.
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28       The <sys/select.h> header shall define the sigset_t type  as  described
29       in <signal.h>.
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31       The  <sys/select.h>  header  shall  define  the  timespec  structure as
32       described in <time.h>.
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34       The <sys/select.h> header shall define the fd_set type as a structure.
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36       The <sys/select.h> header shall define the following symbolic constant,
37       which  shall  have a value suitable for use in #if preprocessing direc‐
38       tives:
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40       FD_SETSIZE  Maximum number of file descriptors in an fd_set structure.
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42       The following shall be declared as functions,  defined  as  macros,  or
43       both. If functions are declared, function prototypes shall be provided.
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45           void FD_CLR(int, fd_set *);
46           int  FD_ISSET(int, fd_set *);
47           void FD_SET(int, fd_set *);
48           void FD_ZERO(fd_set *);
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50       If  implemented as macros, these may evaluate their arguments more than
51       once, so applications should ensure that the arguments they supply  are
52       never expressions with side-effects.
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54       The following shall be declared as functions and may also be defined as
55       macros. Function prototypes shall be provided.
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57           int  pselect(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
58                    const struct timespec *restrict, const sigset_t *restrict);
59           int  select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
60                    struct timeval *restrict);
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62       Inclusion of the <sys/select.h> header may  make  visible  all  symbols
63       from the headers <signal.h> and <time.h>.
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65       The following sections are informative.
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APPLICATION USAGE

68       None.
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RATIONALE

71       None.
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FUTURE DIRECTIONS

74       None.
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SEE ALSO

77       <signal.h>, <sys_time.h>, <sys_types.h>, <time.h>
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79       The System Interfaces volume of POSIX.1‐2008, pselect()
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82       Portions  of  this text are reprinted and reproduced in electronic form
83       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
84       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
85       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
86       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
87       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
88       event of any discrepancy between this version and the original IEEE and
89       The Open Group Standard, the original IEEE and The Open Group  Standard
90       is  the  referee document. The original Standard can be obtained online
91       at http://www.unix.org/online.html .
92
93       Any typographical or formatting errors that appear  in  this  page  are
94       most likely to have been introduced during the conversion of the source
95       files to man page format. To report such errors,  see  https://www.ker‐
96       nel.org/doc/man-pages/reporting_bugs.html .
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100IEEE/The Open Group                  2013                     sys_select.h(0P)
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