1 files changed, 127 insertions, 0 deletions
diff --git a/tests/test-pthread-mutex-type.c b/tests/test-pthread-mutex-type.c
new file mode 100644
index 00000000..34060559
--- /dev/null
+++ b/tests/test-pthread-mutex-type.c
@@ -0,0 +1,127 @@
+/* Test of locking in multithreaded situations.
+   Copyright (C) 2024 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 <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2024.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <pthread.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "macros.h"
+
+/* Returns the effective type of a lock.  */
+static const char *
+get_effective_type (pthread_mutex_t *lock)
+{
+  /* Lock once.  */
+  ASSERT (pthread_mutex_lock (lock) == 0);
+
+  /* Try to lock a second time.  */
+  int err = pthread_mutex_trylock (lock);
+  if (err == 0)
+    return "RECURSIVE";
+  if (err == EBUSY)
+    return "NORMAL";
+
+  /* We can't really check whether the lock is effectively ERRORCHECK, without
+     risking a deadlock.  */
+
+  return "unknown!";
+}
+
+int
+main ()
+{
+  /* Find the effective type of a NORMAL lock.  */
+  const char *type_normal;
+  {
+    pthread_mutex_t lock;
+    pthread_mutexattr_t attr;
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL) == 0);
+    ASSERT (pthread_mutex_init (&lock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+    type_normal = get_effective_type (&lock);
+  }
+
+  /* Find the effective type of an ERRORCHECK lock.  */
+  const char *type_errorcheck;
+  {
+    pthread_mutex_t lock;
+    pthread_mutexattr_t attr;
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK) == 0);
+    ASSERT (pthread_mutex_init (&lock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+    type_errorcheck = get_effective_type (&lock);
+  }
+
+  /* Find the effective type of a RECURSIVE lock.  */
+  const char *type_recursive;
+  {
+    pthread_mutex_t lock;
+    pthread_mutexattr_t attr;
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
+    ASSERT (pthread_mutex_init (&lock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+    type_recursive = get_effective_type (&lock);
+  }
+
+  /* Find the effective type of a DEFAULT lock.  */
+  const char *type_default;
+  {
+    pthread_mutex_t lock;
+    pthread_mutexattr_t attr;
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_DEFAULT) == 0);
+    ASSERT (pthread_mutex_init (&lock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+    type_default = get_effective_type (&lock);
+  }
+
+  /* Find the effective type of a default-initialized lock.  */
+  const char *type_def;
+  {
+    pthread_mutex_t lock;
+    ASSERT (pthread_mutex_init (&lock, NULL) == 0);
+    type_def = get_effective_type (&lock);
+  }
+
+  printf ("PTHREAD_MUTEX_NORMAL     -> type = %s\n", type_normal);
+  printf ("PTHREAD_MUTEX_ERRORCHECK -> type = %s\n", type_errorcheck);
+  printf ("PTHREAD_MUTEX_RECURSIVE  -> type = %s\n", type_recursive);
+  printf ("PTHREAD_MUTEX_DEFAULT    -> type = %s\n", type_default);
+  printf ("Default                  -> type = %s\n", type_def);
+
+  ASSERT (strcmp (type_normal,        "NORMAL") == 0);
+  ASSERT (strcmp (type_errorcheck,    "NORMAL") == 0);
+  ASSERT (strcmp (type_recursive,     "RECURSIVE") == 0);
+
+  ASSERT (strcmp (type_default, type_def) == 0);
+
+  /* This is not required by POSIX, but happens to be the case on all
+     platforms.  */
+  ASSERT (strcmp (type_default,       "NORMAL") == 0);
+  ASSERT (strcmp (type_def,           "NORMAL") == 0);
+
+  return test_exit_status;
+}