Code execution is stuck in gattlib_adapter_scan_enable on RPI

Question

I am a beginner in writing code for BLE development. I am trying to write a straightforward code to scan for BLE devices on RPI using gattlib library in C++.

The program code is as follows:

#include <mutex>
#include <iostream>

#include <gattlib.h>

#define BLE_SCAN_TIMEOUT   5

// We use a mutex to make the BLE connections synchronous
std::mutex g_mutex;

static void ble_discovered_device(void *adapter, const char* addr, const char* name, void *user_data) {
    std::cout << "check 2a\n";
    if (name) {
        printf("Discovered %s - '%s'\n", addr, name);
    } else {
        printf("Discovered %s\n", addr);
    }
}

int main() {
    int ret;
    void *adapter;

    // open adapter for communication
    ret = gattlib_adapter_open(NULL, &adapter);
    if (ret) {
        std::cout << "[Error] Failed to open adapter.\n";
        goto EXIT;
    }

    std::cout << "[INFO] starting scan for BLE devices\n";
        
    std::cout << "check 1\n";

    // lock thread
    g_mutex.lock();
    std::cout << "check 2\n";
    // enable scan
    ret = gattlib_adapter_scan_enable(adapter, ble_discovered_device, BLE_SCAN_TIMEOUT, NULL /* user_data */);
    std::cout << "check 3\n";

    if (ret) {
        std::cout << "[Error] Failed to scan.\n";
        goto EXIT;
    }
        
    // disable scan
    ret = gattlib_adapter_scan_disable(adapter);
    
    // unlock thread
    g_mutex.unlock();

    std::cout << "[INFO] stopping scan\n";
    
    // close adapter
    ret = gattlib_adapter_close(adapter);
    EXIT:     
        std::cout << "[INFO] exit \n";   
}

However the debug statement "check 2a" and "check 3" is not printed. The Bluetooth adapter opens successfully. The terminal logs are as follows:

[INFO] starting scan for BLE devices
check 1
check 2
Fatal Python error: take_gil: PyMUTEX_LOCK(gil->mutex) failed
Python runtime state: unknown

I am using the following command to run my code:

g++ blescan.cpp -o blescan -lgattlib

I have verified that the bluetooth adapter is working on the Raspberry Pi via bluetoothctl.

I am quite unsure what is going wrong here. I am not using python in this code. Thanks for the help!