CODEWITHSUNDEEP
cc-preprocessor
Chris
Chris

Reputation: 773

Any way to get the c preproccessor to ignore all #include's?

Using pycparser to parse a slew of .c source files, but the parser can't handle many things in the #included libraries, and I really don't need them for my purposes. I don't need to have it compile, just need to generate the AST from the specific .c I'm processing. The cpp args i'm passing it right now are: 

cpp_args=["-D__attribute__=","-D__extension__=","-D__builtin_va_list=void*"]

Any ideas?

Thanks!

Upvotes: 1

Views: 1759

Answers (2)

larsks
larsks

Reputation: 311506

Try specifying the -nostdinc option to the preprocessor (and make sure you're not passing any -I options). Given this input in foo.c:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char **argv) {
        return 0;
}

Running:

cpp -nostdinc foo.c

Gives me:

# 1 "foo.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "foo.c"




int main(int argc, char **argv) {
 return 0;
}

And the following errors:

foo.c:1:19: error: no include path in which to search for stdio.h
foo.c:2:20: error: no include path in which to search for stdlib.h
foo.c:3:20: error: no include path in which to search for unistd.h

Upvotes: 4

Martin Beckett
Martin Beckett

Reputation: 96109

One solution would be to use the #include guards

If you have the traditional wrapper in each header, eg.

#ifndef THIS_FILE_H
#define THIS_FILE_H

   // stuff

#endif

Then you could simply #define all the header guard tags you want to ignore

Upvotes: 0

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