Have you left any "extern C" in your frontend program or in any of the used header file. Seems 
like the linker cannot find the poll_event in your frontend code. If it's there, but it's compiled 
with C calling (instead of C++), the name mangling causes it to be invisible to the linker. That 
usually happens if there is somewhere

extern C {
  INT poll_event();
  ... 
}

while it is NOT defined as "extern C" in mfe.h which is used by mfe.cxx.

Stefan

> > Did you include mfe.h as written in elog:1526 ?
> > 
> > Stefan
> 
> 
> Yes I did
> 
> this is my include 
> 
> #include <stdio.h>
> #include <string.h>
> #include <assert.h>
> #include <math.h>
> #include <pthread.h>
> 
> 
> #include "midas.h"
> #include "mscb.h"
> #include "multi.h"
> #include "mscbdev.h"
> #include "mfe.h"
> 
> (I attach my dummy fe)
> 
> What confuses me is that I can compile examples/experiment/ if I copy that to a 
> fresh dir.
> 
> I also copied the CMakeLists from the example:
> 
> #
> # cmake for the muX software
> #
> cmake_minimum_required(VERSION 3.3)
> 
> project(muX)
> 
> #
> # find midas installation, from CMakeLists in examples/experiment
> #
> set(MIDAS_DIR $ENV{MIDASSYS})
> message("MIDAS dir: " ${MIDAS_DIR})
> if (NOT EXISTS $ENV{MIDASSYS})
>   message(FATAL_ERROR "Environment variable $MIDASSYS not defined, aborting.")
> endif()
> 
> set(INC_PATH ${MIDAS_DIR}/include ${MIDAS_DIR}/mxml ${MIDAS_DIR}/mscb/include 
> ${MIDAS_DIR}/drivers/class ${MIDAS_DIR}/drivers/device)
> link_directories($ENV{MIDASSYS}/lib)
> 
> # enable certain compile warnings
> add_compile_options(-Wall -Wformat=2 -Wno-format-nonliteral -Wno-strict-
> aliasing -Wuninitialized -Wno-unused-function)
> 
> set(LIBS -lpthread -lutil -lrt) 
> 
> 
> add_executable(sc_fe_mini sc_fe_mini.cpp)
> target_include_directories(sc_fe_mini PRIVATE ${INC_PATH})
> target_link_libraries(sc_fe_mini mfe midas ${LIBS})