This does not work if you have other #ifdef blocks inside
the DEBUG block. It will resume printing at the first #ifdef
it encounters. Try it with this to see what I mean:
#include <stdio.h>
#ifdef DEBUG
some code here
#ifdef SOLARIS
solaris-specific code here
#endif /* SOLARIS */
this is still debug code
#endif DEBUG
this is normal code
A possible solution would be to keep track of how many
#ifs and #endifs you have seen. Something like this:
my $state = 0;
my $debug = 0;;
while(<>) {
$debug=1,$state++,next if /^\s*#if.*DEBUG/;
$state++ if /^\s*#if/;
$state-- if /^\s*#endif/;
$debug=0,next if $debug && $state==0;
print if $debug==0;
}