From ca9aff6a1646c7fc106bfbb9399b3a1bcb14f18b Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 6 Jul 2013 01:12:28 -0400 Subject: add NFDBITS in sys/select.h with appropriate feature tests the main use for this macro seems to be knowing the correct allocation granularity for dynamic-sized fd_set objects. such usage is non-conforming and results in undefined behavior, but it is widespread in applications. --- include/sys/select.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/sys/select.h') diff --git a/include/sys/select.h b/include/sys/select.h index c5a2877f..e25257d2 100644 --- a/include/sys/select.h +++ b/include/sys/select.h @@ -32,6 +32,9 @@ typedef struct int select (int, fd_set *__restrict, fd_set *__restrict, fd_set *__restrict, struct timeval *__restrict); int pselect (int, fd_set *__restrict, fd_set *__restrict, fd_set *__restrict, const struct timespec *__restrict, const sigset_t *__restrict); +#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) +#define NFDBITS (8*(int)sizeof(long)) +#endif #ifdef __cplusplus } -- cgit v1.2.1