C, Objective-C preprocessor output

Question

Is there a way to get pre-processed C/Objective-C code? I have some files I acquired and would like to see the code produced by some #defines.

Answer 1

From within Xcode:

• Xcode 3: Select the file, then Build → Preprocess.
• Xcode 4: Select the file, then Product → Generate Output → Generate Preprocessed File.

Answer 2

Use the -E command-line argument to gcc or clang. This is documented as: “Preprocess only; do not compile, assemble or link” and indeed it outputs the preprocessed version to stdout.

Answer 3

In Xcode 5: Select the .m file, then Product -> Perform Action -> Preprocess ".m"

Answer 4

On the command line, gcc -E foo.m will show you the preprocessed output (just as it does for normal C/C++ files). Of course, this will also expand any #include or #import statements you may have in your code.