靜態庫和 - 弱系統

Question

我構建了一個靜態庫，它鏈接到其他框架，特別是CoreLocation。我想使用iOS 5提供的功能，但與4.3兼容。

我在發佈的應用程序崩潰時，我與此錯誤啓動它在iOS設備上的4.3：

Date/Time:  2012-08-22 16:44:53.900 +0200 
OS Version:  iPhone OS 4.3.3 (8J3) 
Report Version: 104 

Exception Type: EXC_BREAKPOINT (SIGTRAP) 
Exception Codes: 0x00000001, 0xe7ffdefe 
Crashed Thread: 0 

Dyld Error Message: 
    Symbol not found: _UIKeyboardDidChangeFrameNotification 

我遇到的問題是在這個職位描述：iOS 4 app crashes at startup on iOS 3.1.3: Symbol not found: __NSConcreteStackBlock。

但是，如何建立一個靜態庫時處理？當我設置-weak-lSystem標誌時，我無法編譯。這裏是一個跟蹤：

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: -dynamic not specified, -all_load invalid 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: -dynamic not specified the following flags are invalid: -ObjC 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: can't locate file for: -weak-lSystem 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: -weak-lSystem is not an object file (not allowed in a library) 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk/usr/lib/libxml2.2.dylib is a dynamic library, not added to the static library 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk/usr/lib/libxml2.2.dylib is a dynamic library, not added to the static library 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk/usr/lib/libz.dylib is a dynamic library, not added to the static library 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: file: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk/usr/lib/libz.dylib is a dynamic library, not added to the static library 
Command /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool failed with exit code 1 

解決

見下接受的答案，不要忘記，以紀念在不同版本的Xcode中可選使用的庫。例如：我使用iOS 5的UIKit新通知，但我的部署目標是4.3，所以我需要將此庫標記爲「可選」才能使其工作。 CoreLocation CLGeocoder新的iOS 5類也是如此。

Answer 1

問題是UIKeyboardDidChangeFrameNotification在iOS 4上不可用，因此動態加載器（Dyld）失敗。

從靜態庫開發人員的角度來看，您不必做任何事情。 -weak-lSystem標誌應該在爲應用程序使用靜態庫的Xcode項目中設置（請參閱問題中提到的帖子） - 不在靜態庫的項目中。