了解pthreads,但我无法创建它们 . 这是我的输出和gdb信息:
In main(), creating thread 1
ERROR: return code from pthread_create() is 22 for thread 1
In main(), creating thread 2
ERROR: return code from pthread_create() is 22 for thread 2
In main(), creating thread 3
ERROR: return code from pthread_create() is 22 for thread 3
In main(), creating thread 4
ERROR: return code from pthread_create() is 22 for thread 4
In main(), creating thread 5
ERROR: return code from pthread_create() is 22 for thread 5
Program received signal SIGSEGV, Segmentation fault. 0xb7fb4d8a in
pthread_join (threadid=76038327, thread_return=0x0)
at pthread_join.c:46 46 pthread_join.c: No such file or directory.
这是我的代码:
#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include <errno.h>
#include <pthread.h>
#include <unistd.h>
#define SBUFSIZE 1025
char errorstr[SBUFSIZE];
FILE* inputfp[5];
void* f(void* inpFile) {
fprintf(stderr, "%s\n", (char*)inpFile);
return NULL;
}
int main (int argc, char* argv[]) {
int i;
/* Thread Variables */
pthread_attr_t attr;
pthread_t *th[argc-2]; //one thread for each input file
/* allocate memory for the threads */
for (i = 0; i < (argc-2); i++) {
th[i] = (pthread_t *) malloc(sizeof(pthread_t));
inputfp[i] = fopen(argv[i], "r");
if (!inputfp[i]) {
sprintf(errorstr, "Error Opening Input File: %s", argv[i]);
perror(errorstr);
}
}
/* Create one thread for each input file */
for (i = 1; i < (argc - 1); i++) {
fprintf (stderr, "In main(), creating thread %1d\n", i);
int rc = pthread_create (th[i], &attr, f, inputfp[i-1]);
if (rc) {
printf("ERROR: return code from pthread_create() is %d for thread %d\n",
rc, i);
}
}
/* wait for the threads to finish */
for (i = 1; i < (argc - 1); i++) {
pthread_join(*th[i], 0);
}
return EXIT_SUCCESS;
}
我错过了什么,但我不知道是什么 . 有人可以帮忙吗?谢谢!
编辑:这是我如何根据Joachim Pileborg的建议更改代码 . 我仍然从pthread_create()返回错误22,但pthread_join上的SIGSEGV错误不再发生 .
任何人有任何关于如何让pthread_create()返回0(表示创建成功的线程)的建议?再次感谢!
int main (int argc, char* argv[]) {
int i;
/* Thread Variables */
pthread_attr_t attr;
pthread_t *th[argc-2]; //one thread for each input file
/* allocate memory for the threads */
for (i = 0; i < (argc-2); i++) {
th[i] = (pthread_t *) malloc(sizeof(pthread_t));
printf("%s\n", argv[i+1]);
inputfp[i] = fopen(argv[i+1], "r");
if (!inputfp[i]) {
sprintf(errorstr, "Error Opening Input File: %s", argv[i]);
perror(errorstr);
}
}
/* Create one thread for each input file */
for (i = 0; i < (argc - 2); i++) {
fprintf (stderr, "In main(), creating thread %1d\n", i);
int rc = pthread_create (th[i], &attr, f, inputfp[i]);
if (rc) {
printf("ERROR: return code from pthread_create() is %d for thread %d\n",
rc, i);
}
}
/* wait for the threads to finish */
for (i = 0; i < (argc - 2); i++) {
pthread_join(*th[i], 0);
}
return EXIT_SUCCESS;
}
1 回答
你有一个循环,从零循环到
argc - 3
,并使用正确的索引(零到"size of array minus one" .然后你有两个循环,你从一个循环到
argc - 2
,并使用索引从一个到"size of array" .你应该在所有三个地方使用与第一个相同的循环 .