diff --git a/tools/api_conv.pl b/tools/api_conv.pl
index 7e26145..003a893 100755
--- a/tools/api_conv.pl
+++ b/tools/api_conv.pl
@@ -62,7 +62,7 @@ sub convert($$)
 	return "uint$1_t" if /^CARD(8|16|32)$/;
 	return "int$1_t" if /^INT(8|16|32)$/;
 	return "uint8_t" if $_ eq 'BOOL' or $_ eq 'BYTE';
-	return $_ if /^[A-Z]*_[A-Z_]*$/ or !/^XCB(.+)/;
+	return $_ if /^[A-Z0-9]*_[A-Z0-9_]*$/ or !/^XCB(.+)/;
 	my $const = defined $::const{$_};
 	$_ = $1;