获得＆QUOT;冲突的类型和功能QUOT;在C，为什么呢？ [英] Getting "conflicting types for function" in C, why?

问题描述

我用下面的code：

char dest[5];
char src[5] = "test";

printf("String: %s\n", do_something(dest, src));

char *do_something(char *dest, const char *src)
{
return dest;
}

do_something的实现并不重要。
当我尝试编译上面我得到这两个例外：

The implementation of do_something is not important here. When I try to compile the above I get these two exception:

错误：冲突的类型'do_something'（在printf的调用）
错误：的'do_something'previous隐式声明在这里（在原型线）

"error: conflicting types for 'do_something'" (at the printf call) "error: previous implicit declaration of 'do_something' was here" (at the prototype line)

为什么？

推荐答案

您正在试图调用do_something声明之前。你需要你的printf行前添加一个函数原型：

You are trying to call do_something before you declare it. You need to add a function prototype before your printf line:

char* do_something(char*, const char*);

或者你需要移动的printf线以上函数定义。声明之前无法使用的功能。

Or you need to move the function definition above the printf line. You can't use a function before it is declared.

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