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86 | // Copyright 2021 Jeisson Hidalgo <jeisson.hidalgo@ucr.ac.cr> CC-BY 4.0
#include <assert.h>
#include <inttypes.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
/**
* @brief ...
*/
void* greet(void* data);
int create_threads(uint64_t thread_count);
// procedure main(argc, argv[])
int main(int argc, char* argv[]) {
#if 0
for (int index = 0; index < argc; ++index) {
printf("argv[%d] = '%s'\n", index, argv[index]);
}
return 0;
#endif
int error = EXIT_SUCCESS;
// create thread_count as result of converting argv[1] to integer
// thread_count := integer(argv[1])
uint64_t thread_count = sysconf(_SC_NPROCESSORS_ONLN);
if (argc == 2) {
if (sscanf(argv[1], "%" SCNu64, &thread_count) == 1) {
} else {
fprintf(stderr, "Error: invalid thread count\n");
return 11;
}
}
error = create_threads(thread_count);
return error;
} // end procedure
int create_threads(uint64_t thread_count) {
int error = EXIT_SUCCESS;
// for thread_number := 0 to thread_count do
pthread_t* threads = (pthread_t*) malloc(thread_count * sizeof(pthread_t));
if (threads) {
for (uint64_t thread_number = 0; thread_number < thread_count
; ++thread_number) {
// create_thread(greet, thread_number)
error = pthread_create(&threads[thread_number], /*attr*/ NULL, greet
, /*arg*/ (void*) thread_number);
if (error == EXIT_SUCCESS) {
} else {
fprintf(stderr, "Error: could not create secondary thread\n");
error = 21;
break;
}
}
// print "Hello from main thread"
printf("Hello from main thread\n");
for (uint64_t thread_number = 0; thread_number < thread_count
; ++thread_number) {
pthread_join(threads[thread_number], /*value_ptr*/ NULL);
}
free(threads);
} else {
fprintf(stderr, "Error: could not allocate %" PRIu64 " threads\n"
, thread_count);
error = 22;
}
return error;
}
// procedure greet:
void* greet(void* data) {
// assert(data);
const uint64_t rank = (uint64_t) data;
// print "Hello from secondary thread"
printf("Hello from secondary thread %" PRIu64 "\n", rank);
return NULL;
} // end procedure
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