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c++includec-preprocessorcompiler-flags

What do the include paths/numbers in preprocessed output of icpc (or gcc I guess) mean?

If I use the -E flag when compiling, I get the pre-processed output.

Some of the lines in this output is :- 

# 4 "../Framework.h" 2
# 1 "../Basic.h" 1
# 1 "/usr/include/c++/4.1.2/queue" 1 3

What does it mean? Is there a source that you can point me to for more information?

Solution

  • They are information for the compiler (and later the debugger if the compiler generates debug information) about the processed code. I don't know the exact syntax, but they inform of the include path, location of the '#include' directives in the including file and location of the next line not removed by the preprocessor in the included file. With that information (and counting the lines that are not annotated) the compiler can provide you with diagnostics that will point you to the correct line and how it got included.