macOS下CMake FetchContent_Declare构建libiio的路径异常问题

问题重现 #

我的CMake配置代码如下：

cmake_minimum_required(VERSION 3.10)
include(FetchContent)
project(qluto4)

set(CMAKE_INCLUDE_CURRENT_DIR ON)

message(STATUS "Fetching libiio from github")
FetchContent_Declare(
    libiio
    GIT_REPOSITORY https://github.com/analogdevicesinc/libiio
    GIT_TAG main
)

include_directories(build/_deps/libiio-build)

FetchContent_MakeAvailable(libiio)

执行构建时触发以下错误：

...
[ 30%] Built target iio
[ 31%] Building C object _deps/libiio-build/CMakeFiles/iio-compat.dir/compat.c.o
[ 32%] Building C object _deps/libiio-build/CMakeFiles/iio-compat.dir/dynamic-unix.c.o
[ 34%] Linking C shared library iio.framework/iio
Fixup Current symbolic link
/bin/sh: line 0: cd: /Users/myzinsky/Programming/qluto4/build/iio.framework/Versions: No such file or directory
make[2]: *** [_deps/libiio-build/iio.framework/Versions/0.99/iio] Error 1
make[2]: *** Deleting file `_deps/libiio-build/iio.framework/Versions/0.99/iio'
make[1]: *** [_deps/libiio-build/CMakeFiles/iio-compat.dir/all] Error 2
make: *** [all] Error 2

实际核查发现，iio.framework实际生成在build/_deps/libiio-build/iio.framework路径下，但构建脚本错误地尝试访问build/iio.framework/Versions目录，路径不匹配导致构建失败。

解决方案 #

针对macOS平台下CMake构建framework的路径偏差问题，可通过以下几种方式修复：

• 指定framework生成路径
  在FetchContent_MakeAvailable(libiio)之前添加配置，强制libiio的framework生成到正确的子目录：

set(CMAKE_FRAMEWORK_INSTALL_PREFIX "${CMAKE_CURRENT_BINARY_DIR}/_deps/libiio-build" CACHE PATH "Framework install prefix" FORCE)

• 禁用framework，改用标准动态库
  如果不需要framework格式，直接强制生成普通动态库：

set(BUILD_SHARED_LIBS ON)
set(CMAKE_FRAMEWORK OFF)

将上述两行添加到FetchContent_Declare之前，让libiio以.dylib形式构建，规避framework路径问题。

• 覆盖libiio自身的构建选项
  libiio提供BUILD_FRAMEWORK配置项，可显式关闭：

FetchContent_Declare(
    libiio
    GIT_REPOSITORY https://github.com/analogdevicesinc/libiio
    GIT_TAG main
    OVERRIDE_FIND_PACKAGE
)
set(BUILD_FRAMEWORK OFF CACHE BOOL "Build libiio as framework" FORCE)

通过FORCE参数覆盖libiio内部的默认设置，直接禁用framework构建逻辑。

内容的提问来源于stack exchange，提问作者Matthias