trusty (7) select.h.7posix.gz

NAME

       sys/select.h - select types

SYNOPSIS

       #include <sys/select.h>

DESCRIPTION

       The  <sys/select.h>  header  shall  define  the  timeval  structure  that includes at least the following
       members:

              time_t         tv_sec      Seconds.
              suseconds_t    tv_usec     Microseconds.

       The time_t and suseconds_t types shall be defined as described in <sys/types.h> .

       The sigset_t type shall be defined as described in <signal.h> .

       The timespec structure shall be defined as described in <time.h> .

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

       Each of the following may be declared as a function, or defined as a macro, or both:

       void FD_CLR(int fd, fd_set *fdset)

              Clears the bit for the file descriptor fd in the file descriptor set fdset.

       int FD_ISSET(int fd, fd_set *fdset)

              Returns a non-zero value if the bit for the file descriptor fd is set in the file  descriptor  set
              by fdset, and 0 otherwise.

       void FD_SET(int fd, fd_set *fdset)

              Sets the bit for the file descriptor fd in the file descriptor set fdset.

       void FD_ZERO(fd_set *fdset)

              Initializes the file descriptor set fdset to have zero bits for all file descriptors.

       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 defined as a macro:

       FD_SETSIZE

              Maximum number of file descriptors in an fd_set structure.

       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>,
       <sys/time.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
       IEEE Std 1003.1-2001, pselect(), select()

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 .