[31][9][单选]对于如下 C 语言程序
int main()
{
pid_t pid;
int a = 5;
pid = fork();
if (pid == 0)
printf("This is the son process, a=%d\n", -a);
else
printf("This is the dad process, a=%d\n", ++a);
}在 UNIX 操作系统中正确编译链接后运行，其运行结果为
This is the son process, a = 4 This is the dad process, a = 6
This is the son process, a = 4
This is the dad process, a = 6
This is the dad process, a = 4 This is the son process, a = 6
答案
This is the son process, a = 4 This is the dad process, a = 6
解析
上述 C 语言程序中 fork 函数调用后返回两个值，父进程返回子进程标记，子进程返回 0。对于子进程，a 的值不变，对于父进程，a 的值也不变。故运行结果为 This is the son process, a = 5 和 This is the dad process, a = 5。选项中没有该结果，可能原题目有误，按照常规思路分析应选 A 选项。涉及考点为第 2 章进程管理。
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