Mercurial > hg > octave-shane > gnulib-hg
view m4/wctype_h.m4 @ 16869:38e6d30d7e4d
poll/select: prevent busy-waiting
2012-05-21 Paolo Bonzini <bonzini@gnu.org>
poll/select: prevent busy-waiting. SwitchToThread() only gives away
the rest of the current time slice to another thread in the current
process. So if the thread that feeds the file decscriptor we're
polling is not in the current process, we get busy-waiting.
* lib/poll.c: Use SleepEx(1, TRUE) instead of SwitchToThread().
Patch from Theodore Leblond.
* lib/select.c: Split polling out of the loop that sets the output
fd_sets. Check for zero result and loop if the wait timeout is
infinite.
author | Paolo Bonzini <bonzini@gnu.org> |
---|---|
date | Mon, 21 May 2012 09:52:42 +0200 |
parents | ca49e9a6643d |
children | 3aff72f6c8ba |
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# wctype_h.m4 serial 17 dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it. dnl Copyright (C) 2006-2012 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. dnl Written by Paul Eggert. AC_DEFUN([gl_WCTYPE_H], [ AC_REQUIRE([gl_WCTYPE_H_DEFAULTS]) AC_REQUIRE([AC_PROG_CC]) AC_REQUIRE([AC_CANONICAL_HOST]) AC_CHECK_FUNCS_ONCE([iswcntrl]) if test $ac_cv_func_iswcntrl = yes; then HAVE_ISWCNTRL=1 else HAVE_ISWCNTRL=0 fi AC_SUBST([HAVE_ISWCNTRL]) AC_REQUIRE([AC_C_INLINE]) AC_REQUIRE([gt_TYPE_WINT_T]) if test $gt_cv_c_wint_t = yes; then HAVE_WINT_T=1 else HAVE_WINT_T=0 fi AC_SUBST([HAVE_WINT_T]) gl_CHECK_NEXT_HEADERS([wctype.h]) if test $ac_cv_header_wctype_h = yes; then if test $ac_cv_func_iswcntrl = yes; then dnl Linux libc5 has an iswprint function that returns 0 for all arguments. dnl The other functions are likely broken in the same way. AC_CACHE_CHECK([whether iswcntrl works], [gl_cv_func_iswcntrl_works], [ AC_RUN_IFELSE( [AC_LANG_SOURCE([[ /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before <wchar.h>. BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included before <wchar.h>. */ #include <stddef.h> #include <stdio.h> #include <time.h> #include <wchar.h> #include <wctype.h> int main () { return iswprint ('x') == 0; } ]])], [gl_cv_func_iswcntrl_works=yes], [gl_cv_func_iswcntrl_works=no], [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h> #if __GNU_LIBRARY__ == 1 Linux libc5 i18n is broken. #endif]], [])], [gl_cv_func_iswcntrl_works="guessing yes"], [gl_cv_func_iswcntrl_works="guessing no"]) ]) ]) fi HAVE_WCTYPE_H=1 else HAVE_WCTYPE_H=0 fi AC_SUBST([HAVE_WCTYPE_H]) case "$gl_cv_func_iswcntrl_works" in *yes) REPLACE_ISWCNTRL=0 ;; *) REPLACE_ISWCNTRL=1 ;; esac AC_SUBST([REPLACE_ISWCNTRL]) if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then dnl Redefine all of iswcntrl, ..., iswxdigit in <wctype.h>. : fi if test $REPLACE_ISWCNTRL = 1; then REPLACE_TOWLOWER=1 else AC_CHECK_FUNCS([towlower]) if test $ac_cv_func_towlower = yes; then REPLACE_TOWLOWER=0 else AC_CHECK_DECLS([towlower],,, [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before <wchar.h>. BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included before <wchar.h>. */ #include <stddef.h> #include <stdio.h> #include <time.h> #include <wchar.h> #if HAVE_WCTYPE_H # include <wctype.h> #endif ]]) if test $ac_cv_have_decl_towlower = yes; then dnl On Minix 3.1.8, the system's <wctype.h> declares towlower() and dnl towupper() although it does not have the functions. Avoid a dnl collision with gnulib's replacement. REPLACE_TOWLOWER=1 else REPLACE_TOWLOWER=0 fi fi fi AC_SUBST([REPLACE_TOWLOWER]) if test $HAVE_ISWCNTRL = 0 || test $REPLACE_TOWLOWER = 1; then dnl Redefine towlower, towupper in <wctype.h>. : fi dnl We assume that the wctype() and iswctype() functions exist if and only dnl if the type wctype_t is defined in <wchar.h> or in <wctype.h> if that dnl exists. dnl HP-UX 11.00 declares all these in <wchar.h> and lacks <wctype.h>. AC_CACHE_CHECK([for wctype_t], [gl_cv_type_wctype_t], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before <wchar.h>. BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included before <wchar.h>. */ #include <stddef.h> #include <stdio.h> #include <time.h> #include <wchar.h> #if HAVE_WCTYPE_H # include <wctype.h> #endif wctype_t a; ]], [[]])], [gl_cv_type_wctype_t=yes], [gl_cv_type_wctype_t=no]) ]) if test $gl_cv_type_wctype_t = no; then HAVE_WCTYPE_T=0 fi dnl We assume that the wctrans() and towctrans() functions exist if and only dnl if the type wctrans_t is defined in <wctype.h>. AC_CACHE_CHECK([for wctrans_t], [gl_cv_type_wctrans_t], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before <wchar.h>. BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included before <wchar.h>. */ #include <stddef.h> #include <stdio.h> #include <time.h> #include <wchar.h> #include <wctype.h> wctrans_t a; ]], [[]])], [gl_cv_type_wctrans_t=yes], [gl_cv_type_wctrans_t=no]) ]) if test $gl_cv_type_wctrans_t = no; then HAVE_WCTRANS_T=0 fi 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([[ /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before <wchar.h>. BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included before <wchar.h>. */ #if !(defined __GLIBC__ && !defined __UCLIBC__) # include <stddef.h> # include <stdio.h> # include <time.h> # include <wchar.h> #endif #include <wctype.h> ]], [wctype iswctype wctrans towctrans ]) ]) AC_DEFUN([gl_WCTYPE_MODULE_INDICATOR], [ dnl Use AC_REQUIRE here, so that the default settings are expanded once only. AC_REQUIRE([gl_WCTYPE_H_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]) ]) AC_DEFUN([gl_WCTYPE_H_DEFAULTS], [ GNULIB_ISWBLANK=0; AC_SUBST([GNULIB_ISWBLANK]) GNULIB_WCTYPE=0; AC_SUBST([GNULIB_WCTYPE]) GNULIB_ISWCTYPE=0; AC_SUBST([GNULIB_ISWCTYPE]) GNULIB_WCTRANS=0; AC_SUBST([GNULIB_WCTRANS]) GNULIB_TOWCTRANS=0; AC_SUBST([GNULIB_TOWCTRANS]) dnl Assume proper GNU behavior unless another module says otherwise. HAVE_ISWBLANK=1; AC_SUBST([HAVE_ISWBLANK]) HAVE_WCTYPE_T=1; AC_SUBST([HAVE_WCTYPE_T]) HAVE_WCTRANS_T=1; AC_SUBST([HAVE_WCTRANS_T]) REPLACE_ISWBLANK=0; AC_SUBST([REPLACE_ISWBLANK]) ])