NAPI native module in C++ is executing partially (Included std::thread)

Question

My Node-js native module written with NAPI is executing partially.
I have used multiple threads in it.
While running module sometime it prints that thread is started but sometime it don't.
And in either way module never reach the end of c++ code.
I have tried my c++ code as a standalone application and works fine without any warning or error.
I have turned on exceptional handling in "CMakeList.txt"
C++ 17 support is on because I am using std::filesystem which is working fine.
I am using find_package(Threads REQUIRED) in "CMakeList".

file CMakeList.txt=>

cmake_minimum_required(VERSION 3.15)
# Name of the project (will be the name of the plugin)
project (addon)

set(CMAKE_CXX_STANDARD 17)
# Don't add this line if you will try_compile with boost.
set(CMAKE_CXX_STANDARD_REQUIRED ON)
option(USE_CXX_EXCEPTIONS "Enable C++ exception support" ON)
set(THREADS_PREFER_PTHREAD_FLAG ON)

find_package(Threads REQUIRED)
# Essential include files to build a node addon,
# you should add this line in every CMake.js based project.
include_directories(${CMAKE_JS_INC})

# Declare the location of the source files
file(GLOB SOURCE_FILES "cppsrc/*.cpp" "cppsrc/*.h")

# This line will tell CMake that we're building a shared library
# from the above source files
# named after the project's name
add_library(${PROJECT_NAME} SHARED ${SOURCE_FILES} ${CMAKE_JS_SRC})

# This line will give our library file a .node extension without any "lib" prefix
set_target_properties(${PROJECT_NAME} PROPERTIES PREFIX "" SUFFIX ".node")

# Essential library files to link to a node addon,
# you should add this line in every CMake.js based project.
target_link_libraries(${PROJECT_NAME} ${CMAKE_JS_LIB} ${CMAKE_THREAD_LIBS_INIT})


# Include N-API wrappers
execute_process(COMMAND node -p "require('node-addon-api').include"
    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
    OUTPUT_VARIABLE NODE_ADDON_API_DIR
    )
string(REPLACE "\n" "" NODE_ADDON_API_DIR ${NODE_ADDON_API_DIR})
string(REPLACE "\"" "" NODE_ADDON_API_DIR ${NODE_ADDON_API_DIR})
target_include_directories(${PROJECT_NAME} PRIVATE ${NODE_ADDON_API_DIR})

file package.json=>

{
"name": "test-addon",
"version": "1.0.0",
"description": "",
"author": "",
"license": "ISC",
"scripts": {
"install": "cmake-js compile"
},
"cmake-js": {
  "runtime": "electron",
"runtimeVersion": "5.0.5",
"arch": "x64"
},
"devDependencies": {},
"dependencies": {
  "cmake-js": "^5.3.0",
  "node-addon-api": "^1.6.3"
}
}

the c++ code which is executing partially =>

while (file != filePaths.end()) {
start = timeStamp();
cout << "\n" << "File: " << *file << " \n";

//process Data
pres.readRawDataList(*file);
for (int i = 0; i < hwGuess; i++) {
    begint = (i * pres.rawDataList.size()) / hwGuess;
    endt = (i + (size_t)1) * pres.rawDataList.size() / hwGuess;
    CthreadObj[i].rawData.reserve(pres.rawDataList.size() / hwGuess);
    CthreadObj[i].rawData.insert(CthreadObj[i].Pcomparison::rawData.begin(), pres.rawDataList.begin() + begint, pres.rawDataList.begin() + endt);
threads.push_back(thread([&]() { ExpSub(CthreadObj[i], PthreadObj[i]); }));
}

for (int j = 0; j < hwGuess; j++) {
  cout<<"join total 4 threads\n";
  threads.at(j).join();
}
cout<<hwGuess<<" \n";

cout<<"thread Ends \n";
pfile.writeFile(pres.results, "cppsrc/Output/0.txt");
pres.rawDataList.clear(); pres.rawDataList.shrink_to_fit();
pres.results.clear(); pres.results.shrink_to_fit();
//Processed
cout<<"While ends \n";
file++;

funtion ExpSub=>

ExpSub(Pcomparison& ThreadObjC, Ppattern& ThreadObjP) {

vector<string>::iterator rawIt;

ThreadObjC.lowerCaseRawData();
cout<<"Inside Thread\n";
ThreadObjC.extractEmailAndPassword(":");
ThreadObjC.extractEmailNamesAndWebsites();

hwGuess value is 4

result should be print message "While ends" as in above code and this should happen every time not randomly (check image where it randomly execute "thread inside line"). [enter image description here][1]

https://i.sstatic.net/55TGy.png

Answer 1

Lambda function in c++ does not work perfectly in node.js N-API. So it is best to ignore lambdas in your c++ code. Alternatively you can do something like this

threads.push_back(thread(&class_namespace::ExpSub, ref(CthreadObj[i]), ref(PthreadObj[i])));

and notice you need to use ref() to pass referenced arguments.