The following code example parses the output of xdpyinfo(1x) program. You need the base X client utilities from XFree86 installed (don't know about compatibility with other X distributions). 

#!/usr/bin/perl

use Data::Dumper;

my ($scr, $curr_scr, %screens);

open my $fh, "xdpyinfo|" or die;

while (<$fh>) {
  $scr = $1 if m/^\s*screen\s+#(\d+):/;
  $curr_scr = $1 if m/^\s*default screen number:\s+(\d+)/;
  @{$screens{$scr}}{'x','y'} = ($1, $2)
    if m/^\s*dimensions:\s+(\d+)x(\d+)/;
}

close $fh;

print "Current screen: $curr_scr\n\n";
print Dumper \%screens;

[download]

with the following output on an Xnest with four screens : 

Current screen: 2

$VAR1 = {
          '1' => {
                   'y' => '576',
                   'x' => '768'
                 },
          '3' => {
                   'y' => '576',
                   'x' => '768'
                 },
          '0' => {
                   'y' => '576',
                   'x' => '768'
                 },
          '2' => {
                   'y' => '576',
                   'x' => '768'
                 }
        };

[download]

I don't know how/if the Xinerama screens map to historic X server screens, though (I'm not familiar with Xinerama). Try and see if it works.

In reply to Re: Getting screen resolution by calin
in thread Getting screen resolution by lilphil

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