SDL  2.0
testlock.c
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1 /*
2  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
3 
4  This software is provided 'as-is', without any express or implied
5  warranty. In no event will the authors be held liable for any damages
6  arising from the use of this software.
7 
8  Permission is granted to anyone to use this software for any purpose,
9  including commercial applications, and to alter it and redistribute it
10  freely.
11 */
12 
13 /* Test the thread and mutex locking functions
14  Also exercises the system's signal/thread interaction
15 */
16 
17 #include <signal.h>
18 #include <stdio.h>
19 #include <stdlib.h> /* for atexit() */
20 
21 #include "SDL.h"
22 
23 static SDL_mutex *mutex = NULL;
24 static SDL_threadID mainthread;
25 static SDL_Thread *threads[6];
26 static SDL_atomic_t doterminate;
27 
28 /*
29  * SDL_Quit() shouldn't be used with atexit() directly because
30  * calling conventions may differ...
31  */
32 static void
33 SDL_Quit_Wrapper(void)
34 {
35  SDL_Quit();
36 }
37 
38 void
39 printid(void)
40 {
41  SDL_Log("Process %lu: exiting\n", SDL_ThreadID());
42 }
43 
44 void
45 terminate(int sig)
46 {
47  signal(SIGINT, terminate);
48  SDL_AtomicSet(&doterminate, 1);
49 }
50 
51 void
52 closemutex(int sig)
53 {
54  SDL_threadID id = SDL_ThreadID();
55  int i;
56  SDL_Log("Process %lu: Cleaning up...\n", id == mainthread ? 0 : id);
57  SDL_AtomicSet(&doterminate, 1);
58  for (i = 0; i < 6; ++i)
59  SDL_WaitThread(threads[i], NULL);
60  SDL_DestroyMutex(mutex);
61  exit(sig);
62 }
63 
64 int SDLCALL
65 Run(void *data)
66 {
67  if (SDL_ThreadID() == mainthread)
68  signal(SIGTERM, closemutex);
69  while (!SDL_AtomicGet(&doterminate)) {
70  SDL_Log("Process %lu ready to work\n", SDL_ThreadID());
71  if (SDL_LockMutex(mutex) < 0) {
72  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't lock mutex: %s", SDL_GetError());
73  exit(1);
74  }
75  SDL_Log("Process %lu, working!\n", SDL_ThreadID());
76  SDL_Delay(1 * 1000);
77  SDL_Log("Process %lu, done!\n", SDL_ThreadID());
78  if (SDL_UnlockMutex(mutex) < 0) {
79  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't unlock mutex: %s", SDL_GetError());
80  exit(1);
81  }
82  /* If this sleep isn't done, then threads may starve */
83  SDL_Delay(10);
84  }
85  if (SDL_ThreadID() == mainthread && SDL_AtomicGet(&doterminate)) {
86  SDL_Log("Process %lu: raising SIGTERM\n", SDL_ThreadID());
87  raise(SIGTERM);
88  }
89  return (0);
90 }
91 
92 int
93 main(int argc, char *argv[])
94 {
95  int i;
96  int maxproc = 6;
97 
98  /* Enable standard application logging */
99  SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
100 
101  /* Load the SDL library */
102  if (SDL_Init(0) < 0) {
103  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "%s\n", SDL_GetError());
104  exit(1);
105  }
106  atexit(SDL_Quit_Wrapper);
107 
108  SDL_AtomicSet(&doterminate, 0);
109 
110  if ((mutex = SDL_CreateMutex()) == NULL) {
111  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create mutex: %s\n", SDL_GetError());
112  exit(1);
113  }
114 
115  mainthread = SDL_ThreadID();
116  SDL_Log("Main thread: %lu\n", mainthread);
117  atexit(printid);
118  for (i = 0; i < maxproc; ++i) {
119  char name[64];
120  SDL_snprintf(name, sizeof (name), "Worker%d", i);
121  if ((threads[i] = SDL_CreateThread(Run, name, NULL)) == NULL)
122  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create thread!\n");
123  }
124  signal(SIGINT, terminate);
125  Run(NULL);
126 
127  return (0); /* Never reached */
128 }