cmake将错误链接到外部库

Question

我一直面临着将cmake链接到libass库的问题。我们的项目目录如下图所示

MainApp ( it contains the CmakeLists.txt)
|
|
|--cmake/libs ( this contains FindLibass.cmake)
|
|
|--src
|   |
|   |-Decoder ( it contains the Sources.cmake)
|           |              |--Subtitle.cpp

“FindLibass.cmake”是MainApp的子模块，用于维护Libass外部库和头文件的路径。 “Sources.cmake”是维护解码器特定代码的代码的一部分。

解码器代码已经过修改，可以使用libass头文件，但是在链接到库时。它在代码中失败如下

Subtitle.cpp:(.text+0x68d): undefined reference to `ass_library_init()'
Subtitle.cpp:(.text+0x6fa): undefined reference to `ass_set_message_cb(ass_library*, void (*)(int, char const*, __va_list_tag*, void*), void*)'
Subtitle.cpp:(.text+0x70a): undefined reference to `ass_renderer_init(ass_library*)'

FindLibass.cmake的语法位于

之下

set(LIBASS_INCLUDE_DIR ${LIBASS_SEARCH_PATH})

FIND_PATH(LIBASS_INCLUDE
         NAMES ass/ass.h
         PATHS "${LIBASS_INCLUDE_DIR}/include"  NO_DEFAULT_PATH
 )

FIND_LIBRARY(LIBASS_LIBRARIES
         NAMES "libass.so"
         PATHS "${CMAKE_SOURCE_DIR}/contrib/libass/lib"   NO_DEFAULT_PATH
)