Xcode 9模块循环依赖关系:达尔文-> std ->达尔文

Question

自从在Xcode 9(以前的8.2)中打开我的项目以来，有几个静态库和框架目标由于大量错误而无法编译。此循环依赖关系错误始终位于顶部。

一个例子是libzip的静态库目标。问题来自于这个单一的#，包括系统的zlib库：

#include <zlib.h>

大多数目标都可以通过禁用具有构建设置的启用模块(C和Objective)的模块来解决这一问题。

我有一个Swift/C框架，它定义了几个模块，这不是一个解决方案。

许多错误都与tgmath.h有关，它因对模块玩得不好而臭名昭著。我不知道为什么包含tg计量--它在达尔文模块地图中是显式的。我很想检查一下<module-includes>:28，但我不知道怎么做。

下面是编译错误的一个示例。有人知道如何在Xcode 9中修复这个问题吗？

While building module 'zlib' imported from /Users/.../lib/zipint.h:40:
While building module 'Darwin' imported from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/stddef.h:46:
While building module 'std' imported from /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk/usr/include/tgmath.h:31:
In file included from <module-includes>:1:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/ctype.h:39:15: fatal error: cyclic dependency in module 'Darwin': Darwin -> std -> Darwin
#include_next <ctype.h>
              ^
1 error generated.
While building module 'zlib' imported from /Users/.../lib/zipint.h:40:
While building module 'Darwin' imported from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/stddef.h:46:
In file included from <module-includes>:28:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/9.0.0/include/tgmath.h:37:
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk/usr/include/tgmath.h:31:10: fatal error: could not build module 'std'
#include <complex.h>
 ~~~~~~~~^
2 errors generated.
While building module 'zlib' imported from /Users/.../lib/zipint.h:40:
In file included from <module-includes>:1:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk/usr/include/zlib.h:34:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator11.0.sdk/usr/include/zconf.h:247:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/stddef.h:46:15: fatal error: could not build module 'Darwin'
#include_next <stddef.h>
 ~~~~~~~~~~~~~^
3 errors generated.
In file included from /Users/.../lib/zip_get_compression_implementation.c:36:
/Users/.../lib/zipint.h:40:10: fatal error: could not build module 'zlib'
#include <zlib.h>
 ~~~~~~~~^
4 errors generated.

Answer 1

最后，问题是遗留的自定义头搜索路径。它对SDK，XcodeDefault.xctoolchain/usr/include/c++/v1有一个明确的引用。在搜索路径中包含这些头会破坏依赖周期保护。