tests/test-progs/pthread/src/test_pthread_create_para.cpp

   1 /*
   2   * Copyright (c) 2018, Cornell University
   3   * All rights reserved.
   4   *
   5   * Redistribution and use in source and binary forms, with or
   6   * without modification, are permitted provided that the following
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   9   * Redistributions of source code must retain the above copyright
  10   * notice, this list of conditions and the following disclaimer.
  11   *
  12   * Redistributions in binary form must reproduce the above
  13   * copyright notice, this list of conditions and the following
  14   * disclaimer in the documentation and/or other materials provided
  15   * with the distribution.
  16   *
  17   * Neither the name of Cornell University nor the names of its
  18   * contributors may be used to endorse or promote products derived
  19   * from this software without specific prior written permission.
  20   *
  21   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  22   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  23   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  25   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  26   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  28   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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  32   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  33   * POSSIBILITY OF SUCH DAMAGE.
  34   */
  35
  36 #include <pthread.h>
  37
  38 #include <cstdlib>
  39 #include <iostream>
  40
  41 //------------------------------------------------------------------------
  42 // Create n threads, run them in parallel and wait for them in the master
  43 // thread.
  44 // Each child thread writes its thread id to an output array
  45 //------------------------------------------------------------------------
  46
  47 #define MAX_N_WORKER_THREADS 10
  48
  49 typedef struct
  50 {
  51     int tid;
  52     int* output;
  53 } ThreadArg;
  54
  55 void* func( void* args )
  56 {
  57     ThreadArg* my_args = ( ThreadArg* ) args;
  58
  59     // write tid to this thread's output
  60     (*my_args->output) = my_args->tid;
  61
  62     return nullptr;
  63 }
  64
  65 int main( int argc, const char* argv[] )
  66 {
  67     int n_worker_threads = 0;
  68
  69     // allocate all threads
  70     pthread_t* threads = new pthread_t[MAX_N_WORKER_THREADS];
  71     ThreadArg* t_args = new ThreadArg[MAX_N_WORKER_THREADS];
  72
  73     // create an output array for all threads
  74     int* outputs = new int[MAX_N_WORKER_THREADS];
  75     int ret;
  76
  77     // try to spawn as many worker threads as possible
  78     for ( int tid = 0; tid < MAX_N_WORKER_THREADS; ++tid ) {
  79
  80         // set up thread args
  81         t_args[tid].tid = tid;
  82         t_args[tid].output = outputs + tid;
  83
  84         // spawn thread
  85         ret = pthread_create( threads + tid, nullptr, func, &t_args[tid] );
  86         if (ret != 0) {
  87             break;
  88         }
  89
  90         n_worker_threads++;
  91     }
  92
  93     // sync up all threads
  94     for ( int tid = 0; tid < n_worker_threads; ++tid ) {
  95         pthread_join( threads[tid], nullptr );
  96     }
  97
  98     // verify
  99     bool passed = true;
 100     for ( int i = 0; i < n_worker_threads; ++i ) {
 101         if ( outputs[i] != i ) {
 102             passed = false;
 103         }
 104     }
 105
 106     // clean up
 107     delete[] threads;
 108     delete[] t_args;
 109     delete[] outputs;
 110
 111     // failed if outputs are not correct or no worker thread was spawned
 112     if (!passed || n_worker_threads < 1)
 113         return EXIT_FAILURE;
 114
 115     return EXIT_SUCCESS;
 116 }