Cmake externalproject_add在正确的目录中找不到？

出于某种原因，我在cmake和外部项目的配置步骤方面遇到了问题。它使用了不同的路径，而不是我指定的路径

INCLUDE(ExternalProject)
ExternalProject_Add(project_portaudio
    GIT_REPOSITORY      https://git.assembla.com/portaudio.git
    PREFIX              lib/portaudio
    CONFIGURE_COMMAND   ${SOURCE_DIR}/configure
    BUILD_IN_SOURCE     0
    BUILD_COMMAND       make
    INSTALL_COMMAND     sudo make install
)
ExternalProject_Get_Property(project_portaudio BINARY_DIR)
ExternalProject_Get_Property(project_portaudio SOURCE_DIR)

但是当我成功的时候

make 
[ 11%] Built target record
[ 22%] Built target spectogram
[ 33%] Built target database
[ 44%] Built target match
[ 55%] Built target cmakeDemo
[ 61%] Performing update step for 'project_portaudio'
Current branch master is up to date.
[ 66%] Performing configure step for 'project_portaudio'
/bin/sh: /configure: No such file or directory
make[2]: *** [src/include/record/lib/portaudio/src/project_portaudio-stamp/project_portaudio-configure] Error 127
make[1]: *** [src/include/record/CMakeFiles/project_portaudio.dir/all] Error 2
make: *** [all] Error 2

从这里可以看出。。配置步骤应该在${SOURCE\u DIR}中，而不是${stamp\u DIR}中

---

为什么？

您可能想使用

而不是

${SOURCE\u DIR}

后者指的是CMake变量，该变量很少存在，但前者将扩展到一个目录，作为ExternalProject的源目录