Recently, I get a strange problem when i used popen(3) and pclose(3). Just like this:
最近，当我使用popen（3）和pclose（3）时，我遇到了一个奇怪的问题。像这样：
//a.sh
#!/bin/bash
cat /etc/issue
sleep 3
//b.sh
#!/bin/bash
cat /etc/issue
echo "before sleep"
sleep 3
my C program:
我的C程序：
#include <stdio.h>
int main(void) {
1: FILE *fl = popen("sh a.sh", "r");
2: FILE *fl = popen("sh b.sh", "r");
int t = pclose(fl);
printf("%d\n", t);
return 0;
}
next, i will compile and run this program as 4 steps:
接下来，我将编译并运行此程序为4个步骤：
case 1: comment line 2， then compile and run, the program do not print 0 until the shell cmd terminate.
情况1：注释第2行，然后编译并运行，程序不打印0，直到shell cmd终止。
case 2: comment line 1， then compile and run, the program will terminate right now and it print 13, that is to say the exit status of pclose is 13, i look up the linux errno:
案例2：注释第1行，然后编译并运行，程序将立即终止并打印13，也就是说pclose的退出状态为13，我查找linux errno：
13 EACCES +Permission denied
samebody would help me and tell me the reason? thanks.
同一个人会帮助我并告诉我原因吗？谢谢。