How Can I Remove Comments from C/C Source Code Using GCC?

Removing Comments from C/C Source Code

In C/C programming, comments are essential for adding descriptive notes and documenting code. However, when you need to extract the pure source code without any comments, it can be a tedious task.

Existing Tool for Removing Comments

Rather than manually writing regexes to handle complex scenarios, there's a practical tool that can efficiently remove comments from your C/C source files. The following command utilizes the GNU Compiler Collection (GCC) to accomplish this:

gcc -fpreprocessed -dD -E -P <input_file>

Flags Explanation:

• -fpreprocessed: Generates the preprocessed output without macros being expanded.
• -dD: Disables macro expansion.
• -E: Preprocesses the input without compilation.
• -P: Outputs only the preprocessed code.

Example Usage:

Consider the following source file, test.c, containing comments and macros:

#define foo bar
foo foo foo
#ifdef foo
#undef foo
#define foo baz
#endif
foo foo
/* comments? comments. */
// c++ style comments

Running the command on test.c will produce the following output:

#define foo bar
foo foo foo
#ifdef foo
#undef foo
#define foo baz
#endif
foo foo

As you can see, all comments have been successfully stripped from the code while preserving the actual source structure.

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