Thread: GCC: error check only

  1. #1
    Fortran lover Epy's Avatar
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    GCC: error check only

    Is there a way to "compile" code with GCC while only actually emitting errors, i.e. get the errors/warnings from compiling but not actually compile and creating a file? I ask because I want to check a very large codebase for errors without having to actually compile. It will easily compile without problems, but my bottleneck in the compiling time is the hard drive. I don't actually need the compiled object files, just the errors.

    If nothing else, I suspect that you could direct the output to /dev/null so that writing the output file never takes place. Thoughts?

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    - - - - - - - - oogabooga's Avatar
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    Fortran lover Epy's Avatar
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    Thanks, I saw that when looking earlier, but syntax seems vague, thought for sure it literally only checked language syntax, not errors/warnings.

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    Officially An Architect brewbuck's Avatar
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    Many warnings are only reported when compiling with optimization, as data-flow tracking is necessary to find for instance uninitialized variables etc. A syntax-only check will reliably detect syntax errors but won't report every error/warning that could occur.

    If you use the "-pipe" option to gcc, and output the resulting .o to /dev/null, you should avoid any disk accesses.
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

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    - - - - - - - - oogabooga's Avatar
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    What about using -S to avoid running the assembler at all? You'd still want to direct the resulting .s files to /dev/null.

    Actually, how would you direct output (.s or .o) to /dev/null ?
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  6. #6
    Officially An Architect brewbuck's Avatar
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    Quote Originally Posted by oogabooga View Post
    Actually, how would you direct output (.s or .o) to /dev/null ?
    I think "-o /dev/null" would probably work.
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

  7. #7
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    it looks to me like option -fsyntax-only is what you're looking for.
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