Is there a macro to get the basename and dirname of __FILE__?

Martin Sebor msebor@gmail.com
Thu May 13 23:01:29 GMT 2021


On 5/4/21 9:34 AM, Peng Yu via Gcc-help wrote:
> Hi,
> 
> __FILE__ is the full path of the file used at compile time.
> 
> $ cat a/test.c
> #include <stdio.h>
> int main() {
> 	puts(__FILE__);
> 	return 0;
> }
> $ gcc a/test.c
> $ ./a.out
> a/test.c
> 
> The following discussion says there is no way to get its basename and
> dirname at compile time. Is it still the case?
> 
> Could <string.h> functions be used at compile time for __FILE__ since
> __FILE__ is known at compile time anyway? Thanks.
> 
> https://stackoverflow.com/questions/8487986/file-macro-shows-full-path
> 

There is no macro for just the base name part of __FILE__ that I know
of but it can be computed from __FILE__ using strrchr as someone shows
in the thread:

   (strrchr (__FILE__, '/') ? strrchr (__FILE__, '/') + 1 : __FILE__)

This is evaluated at compile time even without optimization.

Getting just the directory part isn't as easy.

Martin


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