该程序从命令行获取参数,并使用线程显示其主要因素。我正在使用结构在线程之间传递信息。结构有一个2D数组,用于保存参数,然后保存它们的因子。我现在分配的方式允许我访问我的两个参数,并给我一个分段错误(代码中记录了分段错误的位置)。我究竟做错了什么?所有代码均在下面提供。
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
// Global variables
#define MAX_FACTORS (11)
pthread_mutex_t mutex1 = PTHREAD_MUTEX_INITIALIZER;
struct Buffer {
int **factors;
int size;
};
void *factor ( void *buffer );
void *displayFactors (void *factors);
// MAIN
int main (int argc, char* argv[]) {
// Create Buffer
struct Buffer *buffer;
buffer = malloc(sizeof(struct Buffer));
buffer->size = argc - 1;
// Allocate memory for factors 2d array
buffer->factors = malloc(buffer->size);
for( int i = 0; i < buffer->size; i++) {
buffer->factors[i] = calloc(MAX_FACTORS, sizeof(int));
}
pthread_mutex_lock(&mutex1);
if(buffer->size > 0) {
for(int i = 1; i < argc; i++){
buffer->factors[i - 1][0] = atoi(argv[i]);
// ---SEGMENTATION FAULT OCCURS HERE AFTER LOOPING TWICE.----
}
}
else
return 0;
pthread_mutex_unlock(&mutex1);
pthread_t producer;
pthread_t consumer;
pthread_create(&producer, NULL, factor, (void*)buffer);
pthread_create(&consumer, NULL, displayFactors, (void*)buffer);
pthread_join(producer, NULL);
pthread_join(consumer, NULL);
free(buffer->factors);
return 0;
}
// PRODUCER
void *factor ( void *buffer ) {
struct Buffer *prod_buffer = (struct Buffer*)buffer;
pthread_mutex_lock(&mutex1);
// find numbers to factor factors
int i = 0;
while(i < prod_buffer->size) {
// printf("Numbers to factor: %d\n", prod_buffer->factors[i][0]);
prod_buffer->factors[i][0] = prod_buffer->factors[i][0];
i++;
}
// Factor numbers
for(int i = 0; i < prod_buffer->size; i++) {
int j = 1;
int toFactor = prod_buffer->factors[i][0];
while(toFactor % 2 == 0) {
prod_buffer->factors[i][j] = 2;
toFactor = toFactor / 2;
j++;
}
for(int k = 3; k <= toFactor; k += 2) {
while (toFactor % k == 0) {
prod_buffer->factors[i][j] = k;
toFactor /= k;
j++;
}
}
}
pthread_mutex_unlock(&mutex1);
return NULL;
}
// CONSUMER
void *displayFactors (void *buffer) {
struct Buffer *cons_buffer = (struct Buffer*)buffer;
for (int i = 0; i < cons_buffer->size; i++) {
printf("%d: ", cons_buffer->factors[i][0]);
for (int j = 1; j < MAX_FACTORS; j++){
if(cons_buffer->factors[i][j] != 0) printf("%d ", cons_buffer->factors[i][j]);
}
printf("\n");
}
return NULL;
}
EDIT-- 我测试过的论点是4,13,46,72,5和12.结果应该显示: 4:2 2 13:13 46:2 23 72:2 2 2 3 3 5:5 12:2 2 3
感谢您的帮助!
答案 0 :(得分:1)
我使用gdb来调试你的代码,我发现buffer->factors
的大小是8,这还不够。
你应该做
buffer->factors = malloc(buffer->size*sizeof(int *));
此segmentation fault
错误可以解决。
此外,您的代码中还有另一个错误。如果consumer
首先执行,则输出将为空,因此您需要先使用cond
生成producer
exectue。
这里有一些提示:
pthread_cond_t product = PTHREAD_COND_INITIALIZER; /*global*/
pthread_cond_signal(&product); /*In factor function*/
displayFactors
还需要添加互斥锁。
/*in displayFactors function*/
pthread_cond_wait(&product, &mutex1);
在哪里发表这些陈述,你应该自己弄清楚。 希望能帮到你。