sys/select.h — select types
#include <sys/select.h>
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, const 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>.
None.
None.
None.
<signal.h> , <sys/time.h> , <sys/types.h> , <time.h>
XSH pselect
First released in Issue 6. Derived from IEEE Std 1003.1g-2000.
The requirement for the fd_set structure to have a member fds_bits has been removed as per The Open Group Base Resolution bwg2001-005.
SD5-XBD-ERN-6 is applied, reordering the DESCRIPTION.
This reference page is clarified with respect to macros and symbolic constants.
Austin Group Defect 220 is applied, adding const to the second parameter of FD_ISSET().
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