正确使用prctl()的方法

prctl的原型是

int prctl(int option, unsigned long arg2, unsigned long arg3,
          unsigned long arg4, unsigned long arg5);

在man page中,而在header中则声明为可变函数：

extern int prctl (int __option, ...) __THROW;

>当我只需要2个参数时,是否必须用5个参数调用它？
>是否需要将args强制转换为unsigned long？

解决方法:

只需传递您必须传递的内容,然后在其余参数中将0强制转换为无符号数即可,或者完全跳过它们.由于prctl被声明为可变函数,它将相应地处理这种情况.

const char* name = "The user";
if (prctl(PR_SET_NAME, (unsigned long) name,
         (unsigned long)0, (unsigned long)0, (unsigned long)0) == -1)
{
    // handle error
    perror("prctl failed");
    return -1;
}

要么

const char* name = "The user";
if (prctl(PR_SET_NAME, (unsigned long) name) == -1)
{
    // handle error
    perror("prctl failed");
    return -1;
}

标签：variadic,system-calls,glibc,c-3,linux
来源： https://codeday.me/bug/20191118/2031037.html