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Diffstat (limited to '')
| -rw-r--r-- | m4/sys_select_h.m4 | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/m4/sys_select_h.m4 b/m4/sys_select_h.m4 new file mode 100644 index 0000000..2743cd1 --- /dev/null +++ b/m4/sys_select_h.m4 @@ -0,0 +1,110 @@ +# sys_select_h.m4 serial 23 +dnl Copyright (C) 2006-2022 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +AC_DEFUN_ONCE([gl_SYS_SELECT_H], +[ + AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS]) + AC_REQUIRE([AC_C_RESTRICT]) + 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 + #ifdef __cplusplus + "C" + #endif + void *memset (void *, int, unsigned long); + #undef bzero + #define bzero nonexistent_bzero + extern + #ifdef __cplusplus + "C" + #endif + 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]) + if test $ac_cv_header_sys_select_h = yes; then + HAVE_SYS_SELECT_H=1 + else + HAVE_SYS_SELECT_H=0 + fi + AC_SUBST([HAVE_SYS_SELECT_H]) + gl_PREREQ_SYS_H_WINSOCK2 + + dnl Check for declarations of anything we want to poison if the + dnl corresponding gnulib module is not in use. + gl_WARN_ON_USE_PREPARE([[ +/* Some systems require prerequisite headers. */ +#include <sys/types.h> +#if !(defined __GLIBC__ && !defined __UCLIBC__) && HAVE_SYS_TIME_H +# include <sys/time.h> +#endif +#include <sys/select.h> + ]], [pselect select]) +]) + +# gl_SYS_SELECT_MODULE_INDICATOR([modulename]) +# sets the shell variable that indicates the presence of the given module +# to a C preprocessor expression that will evaluate to 1. +# This macro invocation must not occur in macros that are AC_REQUIREd. +AC_DEFUN([gl_SYS_SELECT_MODULE_INDICATOR], +[ + dnl Ensure to expand the default settings once only. + gl_SYS_SELECT_H_REQUIRE_DEFAULTS + gl_MODULE_INDICATOR_SET_VARIABLE([$1]) + dnl Define it also as a C macro, for the benefit of the unit tests. + gl_MODULE_INDICATOR_FOR_TESTS([$1]) +]) + +# Initializes the default values for AC_SUBSTed shell variables. +# This macro must not be AC_REQUIREd. It must only be invoked, and only +# outside of macros or in macros that are not AC_REQUIREd. +AC_DEFUN([gl_SYS_SELECT_H_REQUIRE_DEFAULTS], +[ + m4_defun(GL_MODULE_INDICATOR_PREFIX[_SYS_SELECT_H_MODULE_INDICATOR_DEFAULTS], [ + gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_PSELECT]) + gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SELECT]) + ]) + m4_require(GL_MODULE_INDICATOR_PREFIX[_SYS_SELECT_H_MODULE_INDICATOR_DEFAULTS]) + AC_REQUIRE([gl_SYS_SELECT_H_DEFAULTS]) +]) + +AC_DEFUN([gl_SYS_SELECT_H_DEFAULTS], +[ + dnl Assume proper GNU behavior unless another module says otherwise. + HAVE_PSELECT=1; AC_SUBST([HAVE_PSELECT]) + REPLACE_PSELECT=0; AC_SUBST([REPLACE_PSELECT]) + REPLACE_SELECT=0; AC_SUBST([REPLACE_SELECT]) +]) |