GCC不再实现< varargs.h>. [英] GCC no longer implements <varargs.h>

问题描述

我必须将此代码片段从varargs.h更改为stdarg.h，但我不知道确切如何:

I have to change this code fragment from varargs.h to stdarg.h, but I do not know exactly how to:

#ifndef lint
int ll_log (va_alist)
va_dcl
{
    int event, result;
    LLog   *lp;
    va_list ap;

    va_start (ap);

    lp = va_arg (ap, LLog *);
    event = va_arg (ap, int);

    result = _ll_log (lp, event, ap);

    va_end (ap);

    return result;
}

当我尝试构建它时，编译器会说:

When I try build this, compiler says:

error "GCC no longer implements <varargs.h>."
error "Revise your code to use <stdarg.h>."

我需要编译和运行的程序有一些类似的片段，我需要知道如何更改它们.如果您能写一些例子，我会很满足的.

The program, which I need to compile and run, has a few similar fragments and I need to know how to change them. If you can write some example, I'll be content.

推荐答案

< varargs.h> 是标准的C标头；请使用< stdarg.h> .区别:

<varargs.h> is a pre-standard C header; use <stdarg.h> instead. The differences:

1. 该函数必须至少包含一个命名参数.
2. 该函数必须是原型(使用省略号终止符).
3. va_start 宏的工作方式不同:它带有两个参数，第一个是要初始化的 va_list ，第二个是最后一个命名参数的名称.

1. The function must take at least one named argument.
2. The function must be prototyped (using the ellipsis terminator).
3. The va_start macro works differently: it takes two arguments, the first being the va_list to be initialized and the second the name of the last named argument.

示例:

int ll_log (LLog *llog, ...) {
    int event, result;
    LLog   *lp;
    va_list ap;

    va_start (ap, llog);

    lp = llog;
    event = va_arg (ap, int);

    result = _ll_log (lp, event, ap);

    va_end (ap);
    return result;
}

关于 va_start :gcc忽略了第二个参数，但没有给出正确的参数是不可移植的.

Regarding va_start: gcc ignores the second argument, but not giving the correct one is not portable.

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