Cmake tips

1、cmake to CMakeLists.txt Pass parameters

Command line cmake -DTARGET_CPU:STRING=x86
then , We can do that CMakeLists.txt Using it to help us implement some logic :
if(TARGET_CPU STREQUAL "x86")
#do something
else()
#do something
endif()

2、shell to CMakeLists.txt Pass parameters

a.sh

export TYPES_RELEASE_A20="A20"

export PROJECT_BUILD_TYPE=$1

CMakeLists.txt
if($ENV{PROJECT_BUILD_TYPE} STREQUAL $ENV{TYPES_DEBUG_X86} OR $ENV{PROJECT_BUILD_TYPE} STREQUAL $ENV{TYPES_DEBUG_NDK28}) 

add_definitions(-DAAA_HOST_BBB)

endif()

3、add_definitions Usage of

add_definitions The function and C/C++ Medium #define It's the same

For example, I have the following two files , A source file main.cpp, One CMakeLists.txt
Source file main.cpp

#include <iostream>
int main()
{
#ifdef TEST_IT_CMAKE
    std::cout<<"in ifdef"<<std::endl;
#endif
    std::cout<<"not in ifdef"<<std::endl;
}
cmake file CMakeLists.txt

cmake_minimum_required(VERSION 3.10)
project(optiontest)

add_executable(optiontest main.cpp)
option(TEST_IT_CMAKE "test" ON)
message(${TEST_IT_CMAKE})
if(TEST_IT_CMAKE)
    message("itis" ${TEST_IT_CMAKE})
    add_definitions(-DTEST_IT_CMAKE)
endif()
adopt option Set a variable , And pass add_definitions Convert it to #define TEST_IT_CMAKE

When variables are ON when , The output of the program is

in ifdef
not in ifdef
When variables are OFF when , The output of the program is

not in ifdef