mingw usleep(
1000000) failed with EINVAL, as allowed by POSIX,
but contrary to GNU usage. Rather than implement an accurate
usleep based on select or nanosleep, both of which drag in
dependencies on external libraries, this version intentionally
takes the ceiling in seconds if usleep() is missing.
* modules/usleep: New file.
* m4/usleep.m4 (gl_FUNC_USLEEP): Likewise.
* lib/usleep.c (usleep): Likewise.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Add defaults.
* modules/unistd (Makefile.am): Substitute witnesses.
* lib/unistd.in.h (usleep): Add declaration.
* doc/pastposix-functions/usleep.texi (usleep): Document this.
* MODULES.html.sh (Date and time): Likewise.
* modules/usleep-tests (Depends-on): New test.
* tests/test-usleep.c: New file.
Signed-off-by: Eric Blake <ebb9@byu.net>
2009-11-17 Eric Blake <ebb9@byu.net>
+ usleep: new module
+ * modules/usleep: New file.
+ * m4/usleep.m4 (gl_FUNC_USLEEP): Likewise.
+ * lib/usleep.c (usleep): Likewise.
+ * m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Add defaults.
+ * modules/unistd (Makefile.am): Substitute witnesses.
+ * lib/unistd.in.h (usleep): Add declaration.
+ * doc/pastposix-functions/usleep.texi (usleep): Document this.
+ * MODULES.html.sh (Date and time): Likewise.
+ * modules/usleep-tests (Depends-on): New test.
+ * tests/test-usleep.c: New file.
+
chown: work around OpenBSD bug
* lib/chown.c (rpl_chown): Work around the bug.
* lib/lchown.c (rpl_lchown): Attempt to do likewise.
func_begin_table
func_module gethrxtime
func_module gettime
- func_module settime
func_module posixtm
+ func_module settime
+ func_module usleep
func_module xnanosleep
func_end_table
POSIX specification: @url{http://www.opengroup.org/susv3xsh/usleep.html}
-Gnulib module: ---
+Gnulib module: usleep
Portability problems fixed by Gnulib:
@itemize
+@item
+On some systems, @code{usleep} rejects attempts to sleep longer than 1
+second, as allowed by POSIX:
+mingw.
+@item
+This function is missing on some platforms. However, the replacement
+is designed to be lightweight, and may round to the neareset second;
+use @code{select} or @code{nanosleep} if better resolution is needed:
+IRIX 5.3, Solaris 2.4, older mingw, BeOS.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
@item
-This function is missing on some platforms:
-IRIX 5.3, Solaris 2.4, older mingw, BeOS.
-@item
According to POSIX, the @code{usleep} function may interfere with the program's
use of the @code{SIGALRM} signal. On Linux, it doesn't; on other platforms,
it may.
-@item
-On some systems, @code{usleep} rejects attempts to sleep longer than 1
-second, as allowed by POSIX:
-mingw.
@end itemize
#endif
+#if @GNULIB_USLEEP@
+# if @REPLACE_USLEEP@
+# undef usleep
+# define usleep rpl_usleep
+# endif
+# if !@HAVE_USLEEP@ || @REPLACE_USLEEP@
+/* Pause the execution of the current thread for N microseconds.
+ Returns 0 on completion, or -1 on range error.
+ See the POSIX:2001 specification
+ <http://www.opengroup.org/susv3xsh/sleep.html>. */
+extern int usleep (useconds_t n);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef usleep
+# define usleep(n) \
+ (GL_LINK_WARNING ("usleep is unportable - " \
+ "use gnulib module usleep for portability"), \
+ usleep (n))
+#endif
+
+
#if @GNULIB_WRITE@ && @REPLACE_WRITE@ && @GNULIB_UNISTD_H_SIGPIPE@
/* Write up to COUNT bytes starting at BUF to file descriptor FD.
See the POSIX:2001 specification
--- /dev/null
+/* Pausing execution of the current thread.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+ Written by Eric Blake <ebb9@byu.net>, 2009.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* This file is _intentionally_ light-weight. Rather than using
+ select or nanosleep, both of which drag in external libraries on
+ some platforms, this merely rounds up to the nearest second if
+ usleep() does not exist. If sub-second resolution is important,
+ then use a more powerful interface to begin with. */
+
+#include <config.h>
+
+/* Specification. */
+#include <unistd.h>
+
+#include <errno.h>
+
+#ifndef HAVE_USLEEP
+# define HAVE_USLEEP 0
+#endif
+
+/* Sleep for MICRO microseconds, which can be greater than 1 second.
+ Return -1 and set errno to EINVAL on range error (about 4295
+ seconds), or 0 on success. Interaction with SIGALARM is
+ unspecified. */
+
+int
+usleep (useconds_t micro)
+{
+ unsigned int seconds = micro / 1000000;
+ if (sizeof seconds < sizeof micro && micro / 1000000 != seconds)
+ {
+ errno = EINVAL;
+ return -1;
+ }
+ if (!HAVE_USLEEP && micro % 1000000)
+ seconds++;
+ while ((seconds = sleep (seconds)) != 0);
+
+#undef usleep
+#if !HAVE_USLEEP
+# define usleep(x) 0
+#endif
+ return usleep (micro % 1000000);
+}
-# unistd_h.m4 serial 34
+# unistd_h.m4 serial 35
dnl Copyright (C) 2006-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
GNULIB_UNISTD_H_SIGPIPE=0; AC_SUBST([GNULIB_UNISTD_H_SIGPIPE])
GNULIB_UNLINK=0; AC_SUBST([GNULIB_UNLINK])
GNULIB_UNLINKAT=0; AC_SUBST([GNULIB_UNLINKAT])
+ GNULIB_USLEEP=0; AC_SUBST([GNULIB_USLEEP])
GNULIB_WRITE=0; AC_SUBST([GNULIB_WRITE])
dnl Assume proper GNU behavior unless another module says otherwise.
HAVE_CHOWN=1; AC_SUBST([HAVE_CHOWN])
HAVE_OS_H=0; AC_SUBST([HAVE_OS_H])
HAVE_SYS_PARAM_H=0; AC_SUBST([HAVE_SYS_PARAM_H])
HAVE_UNLINKAT=1; AC_SUBST([HAVE_UNLINKAT])
+ HAVE_USLEEP=1; AC_SUBST([HAVE_USLEEP])
REPLACE_CHOWN=0; AC_SUBST([REPLACE_CHOWN])
REPLACE_CLOSE=0; AC_SUBST([REPLACE_CLOSE])
REPLACE_DUP=0; AC_SUBST([REPLACE_DUP])
REPLACE_SYMLINK=0; AC_SUBST([REPLACE_SYMLINK])
REPLACE_UNLINK=0; AC_SUBST([REPLACE_UNLINK])
REPLACE_UNLINKAT=0; AC_SUBST([REPLACE_UNLINKAT])
+ REPLACE_USLEEP=0; AC_SUBST([REPLACE_USLEEP])
REPLACE_WRITE=0; AC_SUBST([REPLACE_WRITE])
UNISTD_H_HAVE_WINSOCK2_H=0; AC_SUBST([UNISTD_H_HAVE_WINSOCK2_H])
UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=0;
--- /dev/null
+# usleep.m4 serial 1
+dnl Copyright (C) 2009 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 This macro intentionally does not check for select or nanosleep;
+dnl both of those modules can require external libraries.
+AC_DEFUN([gl_FUNC_USLEEP],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ dnl usleep was required in POSIX 2001, but dropped as obsolete in
+ dnl POSIX 2008; therefore, it is not always exposed in headers.
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+ AC_CHECK_FUNCS_ONCE([usleep])
+ AC_CHECK_TYPE([useconds_t], [],
+ [AC_DEFINE([useconds_t], [unsigned int], [Define to an unsigned 32-bit
+ type if <sys/types.h> lacks this type.])])
+ if test $ac_cv_func_usleep = no; then
+ HAVE_USLEEP=0
+ AC_LIBOBJ([usleep])
+ else
+ dnl POSIX allows implementations to reject arguments larger than
+ dnl 999999, but GNU guarantees it will work.
+ AC_CACHE_CHECK([whether usleep allows large arguments],
+ [gl_cv_func_usleep_works],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <unistd.h>
+]], [[return !!usleep (1000000);]])],
+ [gl_cv_func_usleep_works=yes], [gl_cv_func_usleep_works=no],
+ [gl_cv_func_usleep_works="guessing no"])])
+ if test "$gl_cv_func_usleep_works" != yes; then
+ REPLACE_USLEEP=1
+ AC_LIBOBJ([usleep])
+ fi
+ fi
+])
-e 's|@''GNULIB_UNISTD_H_SIGPIPE''@|$(GNULIB_UNISTD_H_SIGPIPE)|g' \
-e 's|@''GNULIB_UNLINK''@|$(GNULIB_UNLINK)|g' \
-e 's|@''GNULIB_UNLINKAT''@|$(GNULIB_UNLINKAT)|g' \
+ -e 's|@''GNULIB_USLEEP''@|$(GNULIB_USLEEP)|g' \
-e 's|@''GNULIB_WRITE''@|$(GNULIB_WRITE)|g' \
-e 's|@''HAVE_CHOWN''@|$(HAVE_CHOWN)|g' \
-e 's|@''HAVE_DUP2''@|$(HAVE_DUP2)|g' \
-e 's|@''HAVE_SYMLINK''@|$(HAVE_SYMLINK)|g' \
-e 's|@''HAVE_SYMLINKAT''@|$(HAVE_SYMLINKAT)|g' \
-e 's|@''HAVE_UNLINKAT''@|$(HAVE_UNLINKAT)|g' \
+ -e 's|@''HAVE_USLEEP''@|$(HAVE_USLEEP)|g' \
-e 's|@''HAVE_DECL_ENVIRON''@|$(HAVE_DECL_ENVIRON)|g' \
-e 's|@''HAVE_DECL_GETLOGIN_R''@|$(HAVE_DECL_GETLOGIN_R)|g' \
-e 's|@''HAVE_OS_H''@|$(HAVE_OS_H)|g' \
-e 's|@''REPLACE_SYMLINK''@|$(REPLACE_SYMLINK)|g' \
-e 's|@''REPLACE_UNLINK''@|$(REPLACE_UNLINK)|g' \
-e 's|@''REPLACE_UNLINKAT''@|$(REPLACE_UNLINKAT)|g' \
+ -e 's|@''REPLACE_USLEEP''@|$(REPLACE_USLEEP)|g' \
-e 's|@''REPLACE_WRITE''@|$(REPLACE_WRITE)|g' \
-e 's|@''UNISTD_H_HAVE_WINSOCK2_H''@|$(UNISTD_H_HAVE_WINSOCK2_H)|g' \
-e 's|@''UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS''@|$(UNISTD_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS)|g' \
--- /dev/null
+Description:
+usleep() function: pause execution of the current thread.
+
+Files:
+lib/usleep.c
+m4/usleep.m4
+
+Depends-on:
+extensions
+sleep
+unistd
+
+configure.ac:
+gl_FUNC_USLEEP
+gl_UNISTD_MODULE_INDICATOR([usleep])
+
+Makefile.am:
+
+Include:
+<unistd.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Eric Blake
--- /dev/null
+Files:
+tests/test-usleep.c
+
+Depends-on:
+time
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-usleep
+check_PROGRAMS += test-usleep
--- /dev/null
+/* Test of usleep() function.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009. */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+int
+main(void)
+{
+ time_t start = time (NULL);
+ ASSERT (usleep (1000000) == 0);
+ ASSERT (start < time (NULL));
+
+ ASSERT (usleep (0) == 0);
+
+ return 0;
+}
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