我可以在 CMakeLists 中使用在工具链文件中定义的 CMAKE_SYSTEM_PROCESSOR 吗? [英] Can I use CMAKE_SYSTEM_PROCESSOR, defined in a toolchain file, in CMakeLists?

问题描述

我想将 Raspberry Pi 作为交叉编译目标添加到使用 CMake 的 C++ 项目中.按照对这个问题的公认回答，我已经成功设置了环境.

I'd like to add Raspberry Pi as a cross compilation target to a C++ project which uses CMake. Following the accepted answer to this question, I've set up the environment successfully.

该项目已经有许多构建目标，所有这些目标都以非常丑陋的方式定义在主 CMakeLists.txt 中(这是一个旧项目).在此文件中，根据 CMAKE_SYSTEM_PROCESSOR 变量设置了一些编译器标志，例如:

The project has many build targets already, all of them defined in the main CMakeLists.txt in a quite ugly way (it's an old project). In this file, there are some compiler flags set, depending on the CMAKE_SYSTEM_PROCESSOR variable, for example:

if (${CMAKE_SYSTEM_PROCESSOR} MATCHES "^arm")
    # do something
endif ()

根据指南，我应该在我的 Raspberry 工具链文件中设置它.我已经添加了 SET(CMAKE_SYSTEM_PROCESSOR arm)，但是我无法从 CMakeLists 访问它，因为它在那里变成了一个空字符串.我对其他变量没有这个问题，比如 CMAKE_SYSTEM_NAME.使用 message()，我可以看到它在工具链文件中仍然可用，但之后变为空.

According to the guide, I should set this in my Raspberry toolchain file. I've added SET(CMAKE_SYSTEM_PROCESSOR arm), but I can't access this from the CMakeLists, because this becomes an empty string there. I don't have this problem with the other variables, like CMAKE_SYSTEM_NAME. Using message(), I can see that it is still available in the toolchain file, but becomes empty after that.

有没有办法在 CMakeLists.txt 中使用 CMAKE_SYSTEM_PROCESSOR?或者，它是故意只在工具链文件中可用吗?

Is there any way to use CMAKE_SYSTEM_PROCESSOR in CMakeLists.txt? Or, is it available only in the toolchain file intentionally?

我使用的是 CMake 2.8.12.2.

I'm using CMake 2.8.12.2.

推荐答案

这似乎毕竟是一个缓存问题 - 在一个干净的目录中构建解决了这个问题.虽然我还是想知道它是怎么变成空字符串的...

It seems this was a caching issue after all - building in a clean directory fixed the problem. Though I still wonder how did it become an empty string...

这篇关于我可以在 CMakeLists 中使用在工具链文件中定义的 CMAKE_SYSTEM_PROCESSOR 吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！