Question

如下:

@implementation Exp
- (int) func:(NSString**) dpStr
{
    //------
    *dpStr = [self func_2];
    //------
}

Now it is being called like this:

int main ()
{
   NSString * str = [[NSString alloc] init];
   int retCode = [Exp func:&str];
   // <----- Now here I m able to access value returned by func ------->

   [str release];    //  <--- It is crashing here 
}

谁能解释为什么它坠毁?

Answer 1

这分配了一个空洞:

NSString * str = [[NSString alloc] init];

www.un.org/Depts/DGACM/index_french.htm 带有一部新载体,显然已经自动发布; 旧价值str 泄漏<>。

int retCode = [Exp func:&str];

飞往<<>>新>>>>>>>的星号,其中:<>,>,>,<>,>,>

[str release];

此处不需要主要<代码>+alloc/-init,也不需要跟踪<代码>-release<>/code>,因为标语由<代码>-func:提供。你们都需要:

NSString *str = nil; [Exp func:&str]; // use str normally

更好的办法是修改<代码>-func:,以便直接返还:

NSString *str = [Exp func]; // use str normally

Then there is no need to pass it by address.

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