calling gcc cpp functionality programmatically

famsinyi · 10-21-2009, 06:31 AM

Hi,

Does anyone know how to call gcc cpp functionality in a program so that the preprocessed output is directed to a memory location rather than a file?

JohnGraham · 10-21-2009, 07:20 AM

The easiest way I can think of is to essentially call

Code:

system("gcc -E -o output.i input.c");

and then output.i and read the file into memory, or mmap it. This puts it in a file first, though... is that really disastrous?

John G

Sergei Steshenko · 10-21-2009, 07:28 AM

'gcc' preprocessor by default outputs to STDOUT, so it's a matter of 'popen' and friends.

smeezekitty · 10-21-2009, 01:13 PM

Quote:

Originally Posted by Sergei Steshenko

'gcc' preprocessor by default outputs to STDOUT, so it's a matter of 'popen' and friends.

STDERR not STDOUT

wje_lq · 10-21-2009, 03:05 PM

Quote:

Originally Posted by smeezekitty

STDERR not STDOUT

From the man page:

Code:

       -E  Stop after the preprocessing stage; do not run the compiler proper.
	   The output is in the form of preprocessed source code, which is
	   sent to the standard output.

	   Input files which don't require preprocessing are ignored.