Categories, NSString and +load

[Andreas Kostler]

Hello everyone,
Please help me on this one. The code snippet below output 
1
0

Hence, [NSObject load] gets called, [NSString load] doesn't. 
Can anyone explain this behaviour?
Kind Regards
 

#include <Foundation/NSString.h>
#include <Foundation/NSAutoreleasePool.h>
static int a = 0;
static int b = 0;

@implementation NSObject (objectCategory)
+(void)load {
 a  = 1;
}
@end

@implementation NSString (stringCategory)
+ (void)load {
 b = 1;
}
@end

int main() {
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
        NSLog (@"%d", a);
        NSLog (@"%d", b);
        [pool release];
}