time: New module.

* lib/time.in.h (time): New declaration.
* lib/time.c: New file.
* m4/time_h.m4 (gl_TIME_H_REQUIRE_DEFAULTS): Initialize GNULIB_TIME.
(gl_TIME_H_DEFAULTS): Initialize REPLACE_TIME.
* m4/time.m4: New file.
* modules/time-h (Makefile.am): Substitute GNULIB_TIME, REPLACE_TIME.
* modules/time: New file.
* tests/test-time-h-c++.cc: Check the signature of
GNULIB_NAMESPACE::time.
* doc/posix-functions/time.texi: Mention the glibc problem and the
'time' module.

2 files changed, 55 insertions, 0 deletions

diff --git a/lib/time.c b/lib/time.c
new file mode 100644
index 0000000000..4e2ee31b48
--- /dev/null
+++ b/lib/time.c
@@ -0,0 +1,41 @@
+/* Provide time() for systems for which it's broken.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <time.h>
+
+#include <stdlib.h>
+#include <sys/time.h>
+
+time_t
+time (time_t *tp)
+{
+  struct timeval tv;
+  time_t tt;
+
+  if (gettimeofday (&tv, NULL) < 0)
+    abort ();
+  tt = tv.tv_sec;
+
+  if (tp)
+    *tp = tt;
+
+  return tt;
+}
diff --git a/lib/time.in.h b/lib/time.in.h
index 87cda21413..3f9af920e3 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -143,6 +143,20 @@ _GL_CXXALIAS_SYS (timespec_getres, int, (struct timespec *ts, int base));
 _GL_CXXALIASWARN (timespec_getres);
 # endif
 
+/* Return the number of seconds that have elapsed since the Epoch.  */
+# if @GNULIB_TIME@
+#  if @REPLACE_TIME@
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    define time rpl_time
+#   endif
+_GL_FUNCDECL_RPL (time, time_t, (time_t *__tp));
+_GL_CXXALIAS_RPL (time, time_t, (time_t *__tp));
+#  else
+_GL_CXXALIAS_SYS (time, time_t, (time_t *__tp));
+#  endif
+_GL_CXXALIASWARN (time);
+# endif
+
 /* Sleep for at least RQTP seconds unless interrupted,  If interrupted,
    return -1 and store the remaining time into RMTP.  See
    <https://pubs.opengroup.org/onlinepubs/9699919799/functions/nanosleep.html>.  */