noble (7) sys_select.h.7posix.gz

Provided by: manpages-posix-dev_2017a-2_all bug

PROLOG
       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.


NAME
       sys/select.h — select types


SYNOPSIS
       #include <sys/select.h>


DESCRIPTION
       The  <sys/select.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.

       The <sys/select.h> header shall define the time_t and suseconds_t types as described in <sys/types.h>.

       The <sys/select.h> header shall define the sigset_t type as described in <signal.h>.

       The <sys/select.h> header shall define the timespec structure as described in <time.h>.

       The <sys/select.h> header shall define the fd_set type as a structure.

       The <sys/select.h> header shall define the following symbolic constant, which shall have a value suitable
       for use in #if preprocessing directives:

       FD_SETSIZE  Maximum number of file descriptors in an fd_set structure.

       The  following  shall  be  declared  as functions, defined as macros, or both. If functions are declared,
       function prototypes shall be provided.

           void FD_CLR(int, fd_set *);
           int  FD_ISSET(int, fd_set *);
           void FD_SET(int, fd_set *);
           void FD_ZERO(fd_set *);

       If implemented as macros, these may evaluate their arguments  more  than  once,  so  applications  should
       ensure that the arguments they supply are never expressions with side-effects.

       The following shall be declared as functions and may also be defined as macros. Function prototypes shall
       be provided.

           int  pselect(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
                    const struct timespec *restrict, const sigset_t *restrict);
           int  select(int, fd_set *restrict, fd_set *restrict, fd_set *restrict,
                    struct timeval *restrict);

       Inclusion of the <sys/select.h> header may make visible all  symbols  from  the  headers  <signal.h>  and
       <time.h>.

       The following sections are informative.


APPLICATION USAGE
       None.


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       <signal.h>, <sys_time.h>, <sys_types.h>, <time.h>

       The System Interfaces volume of POSIX.1‐2017, pselect()


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .