我正在尝试在 C 程序中运行 N 个并发进程。我已经构建了一个简单的示例,它将命令作为参数,为每个命令创建一个 fork,然后执行它。
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc, char **argv)
{
int i;
for(i = 1; i < argc; i++)
{
pid_t pid = fork();
if(pid < 0)
{
fprintf(stderr, "forking error\n");
exit(1);
}
else if(pid > 0)
{
int status;
waitpid(pid, &status, 0);
printf("Command %s has completed successfully by PID=%d\n", argv[i], pid);
}
else
{
char cmd[1024];
sprintf(cmd, "%s", argv[i], i);
system(cmd);
_exit(1);
}
}
printf("Finished\n");
return 0;
}
这似乎可以正确运行进程,但不能同时运行。关于我做错了什么的任何想法?
编辑:我根据建议进行了编辑,但这似乎也不起作用。
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc, char **argv)
{
int i;
pid_t *pids = malloc( sizeof(pid_t) * (argc) );
int *statuses = malloc( sizeof(int) * (argc) );
for(i = 1; i < argc; i++)
{
pid_t pid = fork();
if(pid < 0)
{
fprintf(stderr, "forking error\n");
exit(1);
}
else if(pid > 0)
{
//int status;
//waitpid(pid, &status, 0);
//printf("Command %s has completed successfully by PID=%d\n", argv[i], pid);
pids[i] = pid;
}
else
{
char cmd[1024];
sprintf(cmd, "%s > out.%d", argv[i], i);
system(cmd);
_exit(1);
}
}
int needtowait = 0;
do
{
needtowait = 0;
for(i = 1; i < argc; i++)
{
if(pids[i] > 0)
{
if(waitpid(pids[i], &statuses[i], 0) != 0)
{
pids[i] = 0;
char *successstr = "successfully";
if(statuses[i])
{
successstr = "unsuccessfully";
}
printf("Command %s has completed %s by PID=%d\n", argv[i], successstr, pids[i]);
}
}
else
{
needtowait = 1;
}
sleep(0);
}
} while(needtowait);
printf("Finished!\n");
return 0;
}