ios - iOS插件中的malloc错误

Question

我遇到 malloc 错误:

"pointer being free was not allocated"

我正在尝试为 Unity 构建一个简单的测试 iOS 插件。

H 文件只是声明，M 文件是:

const char* _getDayAsString(int day)
{
    return [[DotWPlugin getDayAsString:day] UTF8String];
}

@implementation DotWPlugin

+ (NSString*)getDayAsString:(int)day
{
    if(day == 0)
        return @"Sunday";
    else if(day == 1)
        return @"Monday";
    else if(day == 2)
        return @"Tuesday";
    else if(day == 3)
        return @"Wednesday";
    else if(day == 4)
        return @"Thursday";
    else if(day == 5)
        return @"Friday";
    else if(day == 6)
        return @"Saturday";
    else
        return @"Invalid";
}

@end

看来问题是我正在尝试将 NSString* 转换为 const char* 但它不喜欢那样。

Answer 1

根据 NSString reference, UTF8String method :

The returned C string is a pointer to a structure inside the string object, which may have a lifetime shorter than the string object and will certainly not have a longer lifetime. Therefore, you should copy the C string if it needs to be stored outside of the memory context in which you called this method.

在您的例子中，getDayAsString: 方法返回的 NSString 在 _getDayAsString() 函数退出时被释放。也就是说，UTF8String方法返回的char*也被释放了。

在您的 _getDayAsString() 中，请创建一个由 UTF8String 方法返回的以 null 结尾的字符串的副本并返回该副本。