Added common include for simple C programs, and threads-intro code

include/common.h

@@ -0,0 +1,21 @@
+#ifndef __common_h__
+#define __common_h__
+
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <assert.h>
+
+double GetTime() {
+    struct timeval t;
+    int rc = gettimeofday(&t, NULL);
+    assert(rc == 0);
+    return (double) t.tv_sec + (double) t.tv_usec/1e6;
+}
+
+void Spin(int howlong) {
+    double t = GetTime();
+    while ((GetTime() - t) < (double) howlong)
+	; // do nothing in loop
+}
+
+#endif // __common_h__

include/common_threads.h

@@ -0,0 +1,33 @@
+#ifndef __common_threads_h__
+#define __common_threads_h__
+
+#include <pthread.h>
+#include <assert.h>
+#include <sched.h>
+
+#ifdef __linux__
+#include <semaphore.h>
+#endif
+
+#define Pthread_create(thread, attr, start_routine, arg) assert(pthread_create(thread, attr, start_routine, arg) == 0);
+#define Pthread_join(thread, value_ptr)                  assert(pthread_join(thread, value_ptr) == 0);
+
+#define Pthread_mutex_lock(m)                            assert(pthread_mutex_lock(m) == 0);
+#define Pthread_mutex_unlock(m)                          assert(pthread_mutex_unlock(m) == 0);
+#define Pthread_cond_signal(cond)                        assert(pthread_cond_signal(cond) == 0);
+#define Pthread_cond_wait(cond, mutex)                   assert(pthread_cond_wait(cond, mutex) == 0);
+
+#define Mutex_init(m)                                    assert(pthread_mutex_init(m, NULL) == 0);
+#define Mutex_lock(m)                                    assert(pthread_mutex_lock(m) == 0);
+#define Mutex_unlock(m)                                  assert(pthread_mutex_unlock(m) == 0);
+#define Cond_init(cond)                                  assert(pthread_cond_init(cond, NULL) == 0);
+#define Cond_signal(cond)                                assert(pthread_cond_signal(cond) == 0);
+#define Cond_wait(cond, mutex)                           assert(pthread_cond_wait(cond, mutex) == 0);
+
+#ifdef __linux__
+#define Sem_init(sem, value)                             assert(sem_init(sem, 0, value) == 0);
+#define Sem_wait(sem)                                    assert(sem_wait(sem) == 0);
+#define Sem_post(sem)                                    assert(sem_post(sem) == 0);
+#endif // __linux__
+
+#endif // __common_threads_h__