Event queue call on object does not work

Mbed OS
1

I use MODSERIAL as this:

MODSERIAL cmdUsb(USBTX, USBRX);

While it is possible to write

void rxCallbackUserContext(string str) {
  cmdUsb.printf("Found string %s. \r\n", str.c_str());
}

and equeue this as

evntQueueUsbOut.call(rxCallbackUserContext, "! unknown command");

it seems not possible to enqueue directly in rxCallbackUserContext(string str) that like

evntQueueUsbOut.call(&cmdUsb, &MODSERIAL::printf, "Found string %s. \r\n", str.c_str());

I receive the following

./mbed-os/events/EventQueue.h: In instantiation of 'void events::EventQueue::context<F, C0, C1>::operator()(ArgTs ...) [with ArgTs = {}; F = AjK::MODSERIAL*; C0 = int (mbed::Stream::*)(const char*, ...); C1 = const char*]':
./mbed-os/events/EventQueue.h:1233:18:   required from 'static void events::EventQueue::function_call(void*) [with F = events::EventQueue::context<AjK::MODSERIAL*, int (mbed::Stream::*)(const char*, ...), const char*>]'
./mbed-os/events/EventQueue.h:754:27:   required from 'int events::EventQueue::call(F) [with F = events::EventQueue::context<AjK::MODSERIAL*, int (mbed::Stream::*)(const char*, ...), const char*>]'
./mbed-os/events/EventQueue.h:766:53:   required from 'int events::EventQueue::call(F, ArgTs ...) [with F = AjK::MODSERIAL*; ArgTs = {int (mbed::Stream::*)(const char*, ...), const char*}]'
./main.cpp:101:76:   required from here
./mbed-os/events/EventQueue.h:1287:13: error: expression cannot be used as a function
 1287 |             f(c0, c1, args...);
      |             ^

Im not really a c++ programmer and im a bit shocked :wink: