initial import

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

inertia.c

@@ -0,0 +1,56 @@
+/*
+ * inertia.c
+ *
+ * Demonstrate a class of programming error, assuming that
+ * threads can't start right away.
+ *
+ * Special notes: On a Solaris 2.5 uniprocessor, this test can't
+ * fail unless a second LWP is created by calling
+ * thr_setconcurrency() because threads are not timesliced.
+ */
+#include <pthread.h>
+#include "errors.h"
+
+void *printer_thread (void *arg)
+{
+    char *string = *(char**)arg;
+
+    printf ("%s\n", string);
+    return NULL;
+}
+
+int main (int argc, char *argv[])
+{
+    pthread_t printer_id;
+    char *string_ptr;
+    int i, status;
+
+#ifdef sun
+    /*
+     * On Solaris 2.5, threads are not timesliced. To ensure
+     * that our two threads can run concurrently, we need to
+     * increase the concurrency level to 2.
+     */
+    DPRINTF (("Setting concurrency level to 2\n"));
+    thr_setconcurrency (2);
+#endif
+    string_ptr = "Before value";
+    status = pthread_create (
+        &printer_id, NULL, printer_thread, (void*)&string_ptr);
+    if (status != 0)
+        err_abort (status, "Create thread");
+
+    /*
+     * Give the thread a chance to get started if it's going to run
+     * in parallel, but not enough that the current thread is likely
+     * to be timesliced. (This is a tricky balance, and the loop may
+     * need to be adjusted on your system before you can see the bug.)
+     */
+    for (i = 0; i < 10000000; i++);
+
+    string_ptr = "After value";
+    status = pthread_join (printer_id, NULL);
+    if (status != 0)
+        err_abort (status, "Join thread");
+    return 0;
+}