ESP32 Forum

Posted: **Wed Apr 06, 2022 12:31 am**

I am trying to use the jsoncpp library (https://github.com/open-source-parsers/jsoncpp)
I have followed the example found in https://github.com/espressif/esp-idf/tr ... import_lib to add third party libraries.
I have edited my CMakeLists.txt in the same way and made sure to set specific build options after reading cmakelist.txt of jsoncpp library as followed:

Code: Select all

idf_component_register(SRCS "main.cpp"
                    INCLUDE_DIRS "."
                    EMBED_TXTFILES gtsr1.pem)

option(BUILD_SHARED_LIBS OFF)
option(BUILD_TESTING OFF)
option(BUILD_OBJECT_LIBS OFF)
option(APPLE OFF)
option(JSONCPP_WITH_TESTS OFF)

function(install)
endfunction()

function(export)
endfunction()

add_subdirectory(jsoncpp)

target_link_libraries(${COMPONENT_LIB} PUBLIC jsoncpp)

cmake configures just fine and the build process proceeds until it reaches the linker part where i get the following error

Code: Select all

[3/4] Linking CXX executable bin/firebase-esp-idf.elf
FAILED: bin/firebase-esp-idf.elf 
: && /home/madjid/.espressif/tools/xtensa-esp32-elf/esp-2021r2-8.4.0/xtensa-esp32-elf/bin/xtensa-esp32-elf-g++  -mlongcalls -Wno-frame-address   CMakeFiles/firebase-esp-idf.elf.dir/project_elf_src_esp32.c.obj  -o bin/firebase-esp-idf.elf  esp-idf/esp_pm/libesp_pm.a. ...............etc..........................  -u newlib_include_syscalls_impl  -u newlib_include_pthread_impl  -u newlib_include_assert_impl  -u __cxa_guard_dummy  -lstdc++  esp-idf/pthread/libpthread.a  -lgcc  esp-idf/cxx/libcxx.a  -ljsoncpp && :
.espressif/../../../../xtensa-esp32-elf/bin/ld: cannot find -ljsoncpp

i can confirm that there is a jsoncpp.a in build/lib directory but the linker cant find anything.
i have tried to fix this for an hour but found nothing really specific to this in the internet. My knowledge with cmake and building in general is limited so i really appreciate if anyone can help

ESP32 Forum

linker cannot find external library

linker cannot find external library