Creating one C file when compiling multiple sources

I have a set of C files to compile using gcc and make. The build process works fine. I want to know if I can obtain -开发者_运维问答 during compilation - one C file containing all the source code without any preprocessor macro.

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One simple was would be to make a file that included all the other source files.

$cat *.c > metafile.c

This would construct such a file, depending on how you set you 'pragma once' and ifndef's this file would probably not be able to compile on its own.

On the other hand, if what you want in a file where all the preprocessor macro's have been unfolded and evaluated, then the answer is to add the following to gcc:

-save-temps

then the file .ii will contain the unfolded and evaluated macros

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If you include all files to the gcc compiler at once you could use

gcc -E main.c other.c another.c

This will also include the stdlib functions maybe use -nostdinc

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You can't - normally you invoke the compiler to compile just a single source file, resulting in an object file. Later you call the linker on all of the object files to create the executable - it doesn't have the original C source code available.

You can, however, create a separate shell script that calls gcc with the -E option just to preprocess the source files, and then use the cat utility to put all the sources in a single file.

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You can use the -save-temps option to get the intermediate outputs. However it will be one output file per source file. Each source file gets compiled separately and represents a compilation unit which can't be mixed up.
You can also use the -E option, however that will only run the preprocessor and not continue compilation.