+ AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+ AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS])
+ AC_CACHE_CHECK([whether <sys/select.h> is self-contained],
+ [gl_cv_header_sys_select_h_selfcontained],
+ [
+ dnl Test against two bugs:
+ dnl 1. On many platforms, <sys/select.h> assumes prior inclusion of
+ dnl <sys/types.h>.
+ dnl 2. On OSF/1 4.0, <sys/select.h> provides only a forward declaration
+ dnl of 'struct timeval', and no definition of this type.
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/select.h>]],
+ [[struct timeval b;]])],
+ [gl_cv_header_sys_select_h_selfcontained=yes],
+ [gl_cv_header_sys_select_h_selfcontained=no])
+ dnl Test against another bug:
+ dnl 3. On Solaris 10, <sys/select.h> provides an FD_ZERO implementation
+ dnl that relies on memset(), but without including <string.h>.
+ if test $gl_cv_header_sys_select_h_selfcontained = yes; then
+ AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[#include <sys/select.h>]],
+ [[int memset; int bzero;]])
+ ],
+ [AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[#include <sys/select.h>]], [[
+ #undef memset
+ #define memset nonexistent_memset
+ extern void *memset (void *, int, unsigned long);
+ #undef bzero
+ #define bzero nonexistent_bzero
+ extern void bzero (void *, unsigned long);
+ fd_set fds;
+ FD_ZERO (&fds);
+ ]])
+ ],
+ [],
+ [gl_cv_header_sys_select_h_selfcontained=no])
+ ])
+ fi
+ ])
+ dnl <sys/select.h> is always overridden, because of GNULIB_POSIXCHECK.
+ gl_CHECK_NEXT_HEADERS([sys/select.h])