On Jul 5, 2005, at 12:56 AM, James Reynolds wrote:
I've tried passing perl pointers to Cocoa methods using the
PerlObjCBridge.
Perl doesn't have pointers, Perl has references. They're
superficially similar, but under the hood they're completely
different beasts.
For example, I'm trying to pass an int by reference:
... Broken example snipped ...
Nothing prints. Here is the Cocoa code, which works.
#import <Foundation/Foundation.h>
int main (int argc, const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int val;
NSString *rawdata = [NSString stringWithFormat:@"12358D"];
NSScanner *scanner = [NSScanner scannerWithString:rawdata];
[scanner scanHexInt:&val];
NSLog (@"%d", val);
[pool release];
return 0;
}
Here's a Perl version that works in both PerlObjCBridge and CamelBones:
#!/usr/bin/perl
use strict;
use warnings;
use Foundation;
# Or, use CamelBones instead... :-)
# use CamelBones qw(:Foundation);
# Allocate enough space to hold a 4-byte int
my $value = "\0" x 4;
# Create a scanner
my $scanner = NSScanner->scannerWithString_('12358D');
# Get a pointer to $value, with pack(). That pointer is returned
# in a 4-byte string scalar, *not* as a numeric value - to
"promote"
# those 4 bytes to a numeric value, we unpack() them:
my $valuePointer = unpack("L", pack("p", $value));
# Scan
$scanner->scanHexInt_($valuePointer);
# Now, use unpack() to interpret the four bytes that were stored in
# $value as an integer
my ($intValue) = unpack("I", $value);
print "Int value: $intValue\n";
sherm--
Cocoa programming in Perl: http://camelbones.sourceforge.net
Hire me! My resume: http://www.dot-app.org
