C++：将 __PRETTY_FUNCTION__ 附加到 c 字符串

Question

我试图在编译时将 __PRETTY_FUNCTION__ 附加到 c 字符串前缀。但它无法编译。而如果我用 __FILE__ 来做，那么它不会失败。

const char* s1= "Prefix" __FILE__;            // works
const char* s2= "Prefix" __PRETTY_FUNCTION__; // compilation error

error: expected ',' or ';' before '__PRETTY_FUNCTION__'
const char* s2 = "Prefix" __PRETTY_FUNCTION__;
                          ^~~~~~~~~~~~~~~~~~~

我正在使用 gcc 和 clang。我错过了什么吗？

Answer 1

来自 GCC documentation for __PRETTY_FUNCTION__:

[__func__ and __PRETTY_FUNCTION__] are variables, not preprocessor macros, and may not be used to initialize char arrays or be concatenated with string literals.

Answer 2

根据 C 标准的 6.10.8.1 Mandatory macros，__FILE__ 是一个字符串文字：

__FILE__ The presumed name of the current source file (a character string literal).

可以在 16.8 预定义宏名称 的 the C++ standard.

的第 1 段中找到类似的语言

然而，根据 6.4.2.2 Predefined identifiers, paragraph 1 of the C standard __func__ 是一个标识符：

The identifier __func__ shall be implicitly declared by the translator as if, immediately following the opening brace of each function definition, the declaration
      static const char __func__[] = "function-name";

8.4.1 总则 the C++ standard states 的第 8 段：

The function-local predefined variable __func__ is defined as if a definition of the form
    static const char __func__[] = "function-name";
had been provided, where function-name is an implementation-defined string. It is unspecified whether such a variable has an address distinct from that of any other object in the program.

假设 GCC 扩展 __PRETTY_FUNCTION__ 作为标准 __func__ 实现，作为实际标识符，它不能与字符串文字连接。

C++：将 __PRETTY_FUNCTION__ 附加到 c 字符串

C++: append __PRETTY_FUNCTION__ to c string

c++

gcc

c-preprocessor