在老專案工程中使用cocoapods，可能會報這個錯誤:library not found for -lPods .

導致這個錯誤可能有兩個原因，這兩個原因在編譯過程中都是有蛛絲馬跡可循的。

原因1：

在 pod install時，就會有告警資訊提示：

xxx target overrides the `OTHER_LDFLAGS` build setting defined in `Pods/Target Support Files/Pods/Pods.debug.xcconfig'. This can lead to problems with the CocoaPods installation

xxx target overrides the `HEADER_SEARCH_PATHS` build setting defined in `Pods/Target Support Files/Pods/Pods.release.xcconfig'. This can lead to problems with the CocoaPods installation

xxx target overrides the `OTHER_CFLAGS` build setting defined in `Pods/Target Support Files/Pods/Pods.release.xcconfig'. This can lead to problems with the CocoaPods installation

This can lead to problems with the CocoaPods installation
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.
    - Use the `$(inherited)` flag, or
    - Remove the build settings from the target.

很明確的告知：通過新增 `$(inherited)` flag 可以解決該問題。

根據除錯確認，OTHER_LDFLAGS 指的是 other linker flags; OTHER_CFLAGS 指的是 other c flags；HEADER_SEARCH_PATHS 指的是 header search paths.

將這三處修改完畢後再次執行pod install，可以發現告警資訊已經不再出現了。

原因2：

在編譯時有如下的警告和錯誤：

1.警告： Target 'Pods' of project 'Pods' was rejected as an implicit dependency for 'libPods.a' because its architectures 'arm64' didn't contain all required architectures 'armv7 arm64'

2.錯誤： ld: library not found for -lpop
clang: error: linker command failed with exit code 1 (use -v to see invocation)

這裡不留神可能警告會被忽略（畢竟在一個老專案中有一些警告很正常），但這個警告才是問題的關鍵。

pod裡面的build選項裡build active architecture only 在 debug情形下預設是 YES, 這裡如果和你專案的該設定不匹配（筆者用來除錯的專案這裡設定就是NO）的話那麼就會報告該錯誤。

在pods裡面的target中挨個修改其配置和原有的工程一致，然後clean編譯，專案即可正常執行。