[vlc-devel] [PATCH 3/3] compat: add clock_getres for darwin

[Marvin Scholz]

---
 compat/clock_getres.c | 57 +++++++++++++++++++++++++++++++++++++++++++
 configure.ac          |  5 ++--
 include/vlc_fixups.h  |  3 +++
 3 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 compat/clock_getres.c

diff --git a/compat/clock_getres.c b/compat/clock_getres.c
new file mode 100644
index 0000000000..e39f97a61f
--- /dev/null
+++ b/compat/clock_getres.c
@@ -0,0 +1,57 @@
+/*****************************************************************************
+ * clock_getres.c: POSIX clock_getres() replacement
+ *****************************************************************************
+ * Copyright © 2020 VLC authors and VideoLAN
+ *
+ * Author: Marvin Scholz <epirat07 at gmail dot com>
+ *
+ * This program 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 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 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, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifndef __APPLE__
+# error clock_getres not implemented on your platform!
+#endif
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#define _DARWIN_C_SOURCE
+#define _POSIX_C_SOURCE  200809L
+
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <mach/clock_types.h>
+
+int clock_getres(clockid_t clock_id, struct timespec *tp)
+{
+    switch (clock_id) {
+        case CLOCK_MONOTONIC:
+        case CLOCK_REALTIME:
+            // For realtime, it is using gettimeofday and for
+            // the monotonic time it is relative to the system
+            // boot time. Both of these use timeval, which has
+            // nanosecond precision only.
+            tp->tv_sec = 0;
+            tp->tv_nsec = NSEC_PER_USEC;
+            break;
+        default:
+            errno = EINVAL;
+            return -1;
+    }
+
+    return 0;
+}
diff --git a/configure.ac b/configure.ac
index c20ab3c75c..3636c5a269 100644
--- a/configure.ac
+++ b/configure.ac
@@ -179,11 +179,12 @@ case "${host_os}" in
     VLC_ADD_LIBS([libvlc vlc],[-Wl,-undefined,dynamic_lookup,-framework,AppKit])
     VLC_ADD_LIBS([libvlccore],[-Wl,-framework,CoreFoundation,-framework,CoreServices])
 
-    dnl macOS 10.11 lacks clock_gettime, introduced with 10.12
+    dnl macOS 10.11 lacks clock_gettime and clock_getres, introduced with 10.12
     AC_LIBOBJ([clock_gettime])
+    AC_LIBOBJ([clock_getres])
     dnl macOS lacks clock_nanosleep
     AC_LIBOBJ([clock_nanosleep])
-    AC_CHECK_FUNCS([clock_gettime clock_nanosleep])
+    AC_CHECK_FUNCS([clock_gettime clock_getres clock_nanosleep])
 
     AC_EGREP_CPP(yes,
             [#import <TargetConditionals.h>
diff --git a/include/vlc_fixups.h b/include/vlc_fixups.h
index a296db0c32..25c7de473e 100644
--- a/include/vlc_fixups.h
+++ b/include/vlc_fixups.h
@@ -672,6 +672,9 @@ FILE *vlc_win32_tmpfile(void);
 # ifndef HAVE_CLOCK_GETTIME
 int clock_gettime(clockid_t clock_id, struct timespec *tp);
 # endif
+# ifndef HAVE_CLOCK_GETRES
+int clock_getres(clockid_t clock_id, struct timespec *tp);
+# endif
 # ifndef HAVE_CLOCK_NANOSLEEP
 int clock_nanosleep(clockid_t clock_id, int flags,
         const struct timespec *rqtp, struct timespec *rmtp);
-- 
2.21.1 (Apple Git-122.3)