c语言执行命令获得返回

execute_command.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int exec_command(char* command, char* out);

int main( int argc, char *argv[] ) {
	char *tmp_buf = malloc(1025);
	char result[4097] = { 0 };
	strcpy(tmp_buf, argv[1]);
	exec_command(tmp_buf, result);
	printf("%s", result);
}

int exec_command(char* command, char* out) {
    FILE *fp;
	char buf[255] = { 0 };
	if ((fp = _popen(command, "r")) == NULL) {
		perror("Fail to popen\n");
		exit(1);
	}
	while (fgets(buf, 255, fp) != NULL) {
		strcat(out, buf);
	}
	_pclose(fp);
	return 0;
}