Building shared library which is executable and linkable using Cmake

Question

How to create an executable shared-library using cmake?

Something like:

libtest.so :: linkable shared library

libtest.so :: executable too

Note: gcc/g++ options are known to achieve the same (https://unix.stackexchange.com/a/223411/152034). But the solution needs cmake way

Answer 1

NOTE: First information regarding this is, there is seemingly an open issue related to cmake. Therefore this can be considered as an indirect solution to achieve the same.

Now follow the illustration using cmake.

test.cpp

#include <stdio.h>                  

void sayHello (char *tag) {         
    printf("%s: Hello!\n", tag);    
}                                

int main (int argc, char *argv[]) { 
    sayHello(argv[0]);              
    return 0;                       
}

ttest/test_test.cpp

#include <stdio.h>                  

extern void sayHello (char*);

int main (int argc, char *argv[]) { 

    printf("\nNow Inside test-test !\n");    

    sayHello(argv[0]);              
    return 0;                       
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.5)

project(pie_test)

#shared-lib as executable
add_library(${PROJECT_NAME} SHARED
            test.cpp
)
target_compile_options(${PROJECT_NAME} PUBLIC "-pie")
target_link_libraries(${PROJECT_NAME} "-pie -Wl,-E")
set_property(TARGET ${PROJECT_NAME} PROPERTY POSITION_INDEPENDENT_CODE 1)

#executable linking to the executable-shared-library
add_executable(test_test
               ttest/test_test.cpp
)
target_link_libraries(test_test pie_test)
set_property(TARGET test_test PROPERTY POSITION_INDEPENDENT_CODE 1)

build.sh

#!/bin/bash

rm -rf build
mkdir build

cd build
cmake .. #--debug-output

make VERBOSE=1
echo "Done!"
echo ""

Reference for gcc-options here.