FirstDay

废话少说，直接正题。

　　今天使用VMware安装OS X 7.0、Xcode 4.2.1开始第一个Objective-C的程序，也就是HelloWorld。以下是从网上copy的代码

1 #import<Foundation/Foundation.h>  
2 int main (int argc, constchar * argv[])  
3 {  
4     NSAutoreleasePool * pool = [[NSAutoreleasePoolalloc] init];
5     NSLog(@"Hello,iphone!");
6     [pool drain];
7     return 0;  
8 }  

但把代码敲进去的时候，编译是失败的，查阅资料得知：

Xcode4.2之后就不使用NSAutoreleasePool这种东西了，改用了@autoreleasepool{...}这种玩意.

查阅的源地址

原文copy如下：

Whenever a new Xcode release and iOs version comes out, there is a lot of new adjustments to make. Apple make a lot of change that are a real pain at the start, but generally make sense after a while.

With Xcode 5, apple have added ARC (automatic reference counting) when you compile the application. This breaks a lot of the old way of doing things, such as release, autorelease, and using NSAutoreleasePool.

So if we have code such as this:

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
…..
[pool release];

We will get an error. But all we need to do is change the format of the code to this:

@autoreleasepool {
….
}

Or you can switch of ARC by setting CLANG_ENABLE_OBJC_ARC to NO in the Build Settings of your app.

You can read more about ARC herehttps://developer.apple.com/library/ios/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html

至此搞定第一个程序，改天再接再厉。

一些可预见的计划：

1. 学习Objective-C基础语法

2. 学习iOS开发基础

FirstDay

原文：http://www.cnblogs.com/insIs0n/p/3541981.html