Johnny Chen | b49b7b5 | 2011-10-01 01:19:45 +0000 | [diff] [blame] | 1 | //===-- main.cpp ------------------------------------------------*- C++ -*-===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | |
| 10 | // C includes |
| 11 | #include <pthread.h> |
| 12 | #include <stdio.h> |
| 13 | #include <stdint.h> |
| 14 | #include <stdlib.h> |
| 15 | #include <unistd.h> |
| 16 | |
| 17 | pthread_t g_thread_1 = NULL; |
| 18 | pthread_t g_thread_2 = NULL; |
| 19 | pthread_t g_thread_3 = NULL; |
| 20 | |
| 21 | char *g_char_ptr = NULL; |
| 22 | |
| 23 | void |
| 24 | do_bad_thing_with_location(char *char_ptr, char new_val) |
| 25 | { |
| 26 | *char_ptr = new_val; |
| 27 | } |
| 28 | |
| 29 | uint32_t access_pool (uint32_t flag = 0); |
| 30 | |
| 31 | uint32_t |
| 32 | access_pool (uint32_t flag) |
| 33 | { |
| 34 | static pthread_mutex_t g_access_mutex = PTHREAD_MUTEX_INITIALIZER; |
| 35 | if (flag == 0) |
| 36 | ::pthread_mutex_lock (&g_access_mutex); |
| 37 | |
| 38 | char old_val = *g_char_ptr; |
| 39 | if (flag != 0) |
| 40 | do_bad_thing_with_location(g_char_ptr, old_val + 1); |
| 41 | |
| 42 | if (flag == 0) |
| 43 | ::pthread_mutex_unlock (&g_access_mutex); |
| 44 | return *g_char_ptr; |
| 45 | } |
| 46 | |
| 47 | void * |
| 48 | thread_func (void *arg) |
| 49 | { |
| 50 | uint32_t thread_index = *((uint32_t *)arg); |
| 51 | printf ("%s (thread index = %u) startng...\n", __FUNCTION__, thread_index); |
| 52 | |
| 53 | uint32_t count = 0; |
| 54 | uint32_t val; |
| 55 | while (count++ < 15) |
| 56 | { |
| 57 | // random micro second sleep from zero to 3 seconds |
| 58 | int usec = ::rand() % 3000000; |
| 59 | printf ("%s (thread = %u) doing a usleep (%d)...\n", __FUNCTION__, thread_index, usec); |
| 60 | ::usleep (usec); |
| 61 | |
| 62 | if (count < 7) |
| 63 | val = access_pool (); |
| 64 | else |
| 65 | val = access_pool (1); |
| 66 | |
| 67 | printf ("%s (thread = %u) after usleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count); |
| 68 | } |
| 69 | printf ("%s (thread index = %u) exiting...\n", __FUNCTION__, thread_index); |
| 70 | return NULL; |
| 71 | } |
| 72 | |
| 73 | |
| 74 | int main (int argc, char const *argv[]) |
| 75 | { |
| 76 | int err; |
| 77 | void *thread_result = NULL; |
| 78 | uint32_t thread_index_1 = 1; |
| 79 | uint32_t thread_index_2 = 2; |
| 80 | uint32_t thread_index_3 = 3; |
| 81 | |
| 82 | g_char_ptr = (char *)malloc (1); |
| 83 | *g_char_ptr = 0; |
| 84 | |
| 85 | // Create 3 threads |
| 86 | err = ::pthread_create (&g_thread_1, NULL, thread_func, &thread_index_1); |
| 87 | err = ::pthread_create (&g_thread_2, NULL, thread_func, &thread_index_2); |
| 88 | err = ::pthread_create (&g_thread_3, NULL, thread_func, &thread_index_3); |
| 89 | |
| 90 | printf ("Before turning all three threads loose...\n"); // Set break point at this line. |
| 91 | |
| 92 | // Join all of our threads |
| 93 | err = ::pthread_join (g_thread_1, &thread_result); |
| 94 | err = ::pthread_join (g_thread_2, &thread_result); |
| 95 | err = ::pthread_join (g_thread_3, &thread_result); |
| 96 | |
| 97 | return 0; |
| 98 | } |