ObjC: proper use of property and synthesize?

Question

Does anyone know why this code is running into compilation errors? I\'m compiling it on Catalina using clang. I posted a similar issue here but that was when I was trying to c

Answer 1

Declaring a property with name a produces a getter with name a, not getA. This is what the first warning is about: "instance method '-getA' not found"

Answer 2

This works on my system (macOS):

#import <Foundation/Foundation.h>

@interface A: NSObject

@property int a;

@end

@implementation A {
  int a;
}
@synthesize a;

-(int) getMyValue {
return a;
}

@end

int main () {
  @autoreleasepool {
    A *a = [[A alloc] init];
   [a setA:99];
   NSLog (@"value = %d", [a getMyValue]);
 }
  return 0;
}

If file is saved as synth.m the terminal command is: clang synth.m -framework Foundation -o synth && ./synth

Answer 3

The getter/setter pair is synthesized as

-(int)a;
-(void)setA:(int)val;

So you need:

int main (int argc, char * argv[])
{
  @autoreleasepool {
    A *a = [[A alloc] init];

    [a setA:99];
    int v = [a a];
    NSLog (@" %d\n", v);
  }
  return 0;
}