更新时间:2023-02-03 12:37:13
您可以简单地测试变量,例如:
You can simply test the variable as such, e.g.:
find_library(LUA_LIB lua)
if(NOT LUA_LIB)
message(FATAL_ERROR "lua library not found")
endif()
输出示例:
CMake Error at CMakeLists.txt:99 (message):
lua library not found
-- Configuring incomplete, errors occurred!
请注意,我们使用
if(NOT LUA_LIB)
而不是
if(NOT ${LUA_LIB})
$ b b
,因为不同的语义。
使用 $ {}
,变量 LUA_LIB
code> if()被求值。作为评估的
部分,内容将被解释为变量名称,
,除非它匹配常量的定义。这不是我们想要的。
With ${}
, the variable LUA_LIB
is substitued before if()
is evaluated. As
part of the evaluation the content would then be interpreted as variable name,
unless it matches the definition of a constant. And this isn't what we want.