initial import

from
http://www.informit.com/store/programming-with-posix-threads-9780201633924

mutex_attr.c

@@ -0,0 +1,35 @@
+/*
+ * mutex_attr.c
+ *
+ * Create a mutex using a non-default attributes object,
+ * mutex_attr. If the implementation supports the pshared
+ * attribute, the mutex is created "process private" so that it
+ * could be used to synchronize between threads in separate
+ * address spaces. (Note that, to create a "process shared"
+ * mutex, the pthread_mutex_t itself must be placed in shared
+ * memory that is accessible to all threads using the mutex.)
+ */
+#include <pthread.h>
+#include "errors.h"
+
+pthread_mutex_t mutex;
+
+int main (int argc, char *argv[])
+{
+    pthread_mutexattr_t mutex_attr;
+    int status;
+
+    status = pthread_mutexattr_init (&mutex_attr);
+    if (status != 0)
+        err_abort (status, "Create attr");
+#ifdef _POSIX_THREAD_PROCESS_SHARED
+    status = pthread_mutexattr_setpshared (
+        &mutex_attr, PTHREAD_PROCESS_PRIVATE);
+    if (status != 0)
+        err_abort (status, "Set pshared");
+#endif
+    status = pthread_mutex_init (&mutex, &mutex_attr);
+    if (status != 0)
+        err_abort (status, "Init mutex");
+    return 0;
+}