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在Object-C中，系统会自动为每个对象管理引用计数器。每当创建新对象时，初始计数设置为1。为了保持对对象的引用，需要通过调用retain()方法来增加计数，需要调用release()方法来减少计数。当计数为0时，系统会自动发送dealloc()消息释放对象的内存。

代码示例

1. ClassA.h

#import 
   
    @interface ClassA : NSObject@end
   

2. ClassA.m

#import "ClassA.h"@implementation ClassA- (void) dealloc {  printf("Deallocing ClassA\n");  [super dealloc];}@end

3. main.m

#include 
   
    #include "ClassA.h"int main(int argc, const char *argv[]) {  printf("test case 1:\n");  ClassA *a1 = [[ClassA alloc] init];  ClassA *a2 = [[ClassA alloc] init];    printf("a1 retain count: %i\n", [a1 retainCount]);  printf("a2 retain count: %i\n", [a2 retainCount]);    printf("test case 2:\n");  [a1 retain]; // 2  [a1 retain]; // 3  [a2 retain]; // 2    printf("a1 retain count: %i\n", [a1 retainCount]);  printf("a2 retain count: %i\n", [a2 retainCount]);    printf("test case 3:\n");  [a1 release]; // 2  [a2 release]; // 1    printf("a1 retain count: %i\n", [a1 retainCount]);  printf("a2 retain count: %i\n", [a2 retainCount]);    [a1 release]; // 0  [a2 release]; // 0    printf("Deallocing ClassA\n");  printf("Deallocing ClassA\n");    return 0;}
   

编译运行

gcc -fconstant-string-class=NSConstantString -c main.m -I /GNUstep/System/Library/Headersgcc -c ClassA.m -I /GNUstep/System/Library/Headersgcc main.o ClassA.o -o main -L /GNUstep/System/Library/Libraries/ -lobjc -lgnustep-base./main.exe

说明