GCC预处理器输出中的调试信息 [英] Debugging information in GCC preprocessor output

问题描述

我正在检查由GCC生成的预处理输出，我在 .i 文件中看到很多这些，我使用 save-temps flag：

I was inspecting the preprocessed output generated by GCC, and I see a lot of these in the .i file that I generated using the -save-temps flag:

# 8 "/usr/include/i386-linux-gnu/gnu/stubs.h" 2 3 4

code> stubs.h 是什么意思？它似乎是由预处理器插入的某种调试信息，并允许编译器发出引用此信息的错误消息。

What do the numbers before and after the absolute path of stubs.h mean? It seems to be some kind of debugging information that is inserted by the preprocessor and allows the compiler to issue error messages referring to this information. These lines do not affect the program itself, but what specifically is each number for?

推荐答案

基于文档，之前的文件名是行号。文件名后面的数字是一个标志，意味着以下内容：

Based on the documentation the number before the filename is the line number. The numbers after the file name are a flag and mean the following:

• 1


• 2 表示返回文件（在包含另一个文件之后）。


• 3 表示以下文本来自系统头文件，因此应禁止某些警告。


• 4 表示以下文本应被视为包含在隐式外部C块中。

• 1 indicates the start of a new file.
• 2 indicates returning to a file (after having included another file).
• 3 indicates that the following text comes from a system header file, so certain warnings should be suppressed.
• 4 indicates that the following text should be treated as being wrapped in an implicit extern "C" block.

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