1 /*
2   Copyright (C) 1997-2020 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 /* Simple test of the SDL threading code */
14 
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <signal.h>
18 #include <string.h>
19 
20 #include "SDL.h"
21 
22 #define NUMTHREADS 10
23 
24 static SDL_atomic_t time_for_threads_to_die[NUMTHREADS];
25 
26 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
27 static void
quit(int rc)28 quit(int rc)
29 {
30     SDL_Quit();
31     exit(rc);
32 }
33 
34 int SDLCALL
SubThreadFunc(void * data)35 SubThreadFunc(void *data)
36 {
37     while (!*(int volatile *) data) {
38         ;                       /* SDL_Delay(10); *//* do nothing */
39     }
40     return 0;
41 }
42 
43 int SDLCALL
ThreadFunc(void * data)44 ThreadFunc(void *data)
45 {
46     SDL_Thread *sub_threads[NUMTHREADS];
47     int flags[NUMTHREADS];
48     int i;
49     int tid = (int) (uintptr_t) data;
50 
51     SDL_Log("Creating Thread %d\n", tid);
52 
53     for (i = 0; i < NUMTHREADS; i++) {
54         char name[64];
55         SDL_snprintf(name, sizeof (name), "Child%d_%d", tid, i);
56         flags[i] = 0;
57         sub_threads[i] = SDL_CreateThread(SubThreadFunc, name, &flags[i]);
58     }
59 
60     SDL_Log("Thread '%d' waiting for signal\n", tid);
61     while (SDL_AtomicGet(&time_for_threads_to_die[tid]) != 1) {
62         ;                       /* do nothing */
63     }
64 
65     SDL_Log("Thread '%d' sending signals to subthreads\n", tid);
66     for (i = 0; i < NUMTHREADS; i++) {
67         flags[i] = 1;
68         SDL_WaitThread(sub_threads[i], NULL);
69     }
70 
71     SDL_Log("Thread '%d' exiting!\n", tid);
72 
73     return 0;
74 }
75 
76 int
main(int argc,char * argv[])77 main(int argc, char *argv[])
78 {
79     SDL_Thread *threads[NUMTHREADS];
80     int i;
81 
82     /* Enable standard application logging */
83     SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
84 
85     /* Load the SDL library */
86     if (SDL_Init(0) < 0) {
87         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
88         return (1);
89     }
90 
91     signal(SIGSEGV, SIG_DFL);
92     for (i = 0; i < NUMTHREADS; i++) {
93         char name[64];
94         SDL_snprintf(name, sizeof (name), "Parent%d", i);
95         SDL_AtomicSet(&time_for_threads_to_die[i], 0);
96         threads[i] = SDL_CreateThread(ThreadFunc, name, (void*) (uintptr_t) i);
97 
98         if (threads[i] == NULL) {
99             SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create thread: %s\n", SDL_GetError());
100             quit(1);
101         }
102     }
103 
104     for (i = 0; i < NUMTHREADS; i++) {
105         SDL_AtomicSet(&time_for_threads_to_die[i], 1);
106     }
107 
108     for (i = 0; i < NUMTHREADS; i++) {
109         SDL_WaitThread(threads[i], NULL);
110     }
111     SDL_Quit();
112     return (0);
113 }
114