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 = 4

This is the son process, a = 5

This is the dad process, a = 5

答案

This is the son process, a = 5

This is the dad process, a = 5

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。