> How do I solve mismatched declarations in the mfe (or other places in the midas code)?

I run into such problems all the time. My solution? I grep for the function name in my code and in the header file,
then look very carefully at the definition to confirm that all the argument declarations are the same in both
places. Sometimes my eyes do not see the difference and I ask for a "second pair of eyes".

In your case, you have a mismatch between functions in mfe.h and in your frontend. The difference
is "int source" in mfe.h and "int source[]" in your code.

Because C++ permits functions with identical namesm but different arguments, the compiler thinks
you did this on purpose and does not complain. Later, of course, the linker bombs,
but all it can report at this stage, is what you see "function not found"... Then you grep your code
for the missing function, check arguments, rinse, repeat.

Before C++, the C compiler would probably had complained about the mismatch, except that MIDAS
did not have an mfe.h header file definitions for all this stuff until just now, so again, the mismatch would
have gone unnoticed, unfixed.

K.O.



> It is having issues with the midas defined BOOL/... types. This 
> is what I get for a minimal scfe:
> 
> [ 12%] Building CXX object CMakeFiles/sc_fe_mini.dir/sc_fe_mini.cpp.o
> [ 25%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/drivers/class/hv.cxx.o
> [ 37%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/drivers/class/multi.cxx.o
> [ 50%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/drivers/device/nulldev.cxx.o
> [ 62%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/drivers/bus/null.cxx.o
> [ 75%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/drivers/device/mscbdev.cxx.o
> [ 87%] Building CXX object CMakeFiles/sc_fe_mini.dir/home/frederik/packages/midas/mscb/src/mscb.cxx.o
> [100%] Linking CXX executable sc_fe_mini
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `_readout_thread':
> /home/frederik/packages/midas/src/mfe.cxx:1271: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `check_polled_events':
> /home/frederik/packages/midas/src/mfe.cxx:1601: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/src/mfe.cxx:1643: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `readout_enable(unsigned int)':
> /home/frederik/packages/midas/src/mfe.cxx:1158: undefined reference to `interrupt_configure(int, int, long)'
> /home/frederik/packages/midas/src/mfe.cxx:1156: undefined reference to `interrupt_configure(int, int, long)'
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `initialize_equipment':
> /home/frederik/packages/midas/src/mfe.cxx:614: undefined reference to `interrupt_configure(int, int, long)'
> /home/frederik/packages/midas/src/mfe.cxx:649: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `scheduler':
> /home/frederik/packages/midas/src/mfe.cxx:1890: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/src/mfe.cxx:1932: undefined reference to `poll_event(int, int, unsigned int)'
> /home/frederik/packages/midas/build/libmfe.a(mfe.cxx.o): In function `main':
> /home/frederik/packages/midas/src/mfe.cxx:2701: undefined reference to `interrupt_configure(int, int, long)'
> /home/frederik/packages/midas/src/mfe.cxx:2702: undefined reference to `interrupt_configure(int, int, long)'
> collect2: error: ld returned 1 exit status
> make[2]: *** [sc_fe_mini] Error 1
> make[1]: *** [CMakeFiles/sc_fe_mini.dir/all] Error 2
> make: *** [all] Error 2
> 
> 
> This is my cmakelists for my user code:
> 
> #
> # cmake for the muX software
> #
> cmake_minimum_required(VERSION 3.3)
> 
> project(muX)
> 
> #
> # find installations
> #
> set(MIDAS_DIR $ENV{MIDASSYS})
> message("MIDAS dir: " ${MIDAS_DIR})
> 
> #
> # set directories
> #
> set(MIDASBUILD_DIR ${MIDAS_DIR}/build)
> set(MIDASINCLUDE_DIR ${MIDAS_DIR}/include)
> set(MXML_DIR ${MIDAS_DIR}/mxml)
> set(MSCB_DIR ${MIDAS_DIR}/mscb)
> set(DRV_DIR ${MIDAS_DIR}/drivers)
> 
> 
> #
> # drivers, libs
> #
> set(DRIVERS
>     ${MIDAS_DIR}/drivers/class/hv
>     ${MIDAS_DIR}/drivers/class/multi
>     ${MIDAS_DIR}/drivers/device/nulldev
>     ${MIDAS_DIR}/drivers/bus/null
> )
> set(MIDASLIB ${MIDASBUILD_DIR}/libmidas.a)
> set(FELIB ${MIDASBUILD_DIR}/libmfe.a)
> 
> #
> # sc_fe
> #
> add_executable(sc_fe_mini
>         sc_fe_mini.cpp
>         ${DRIVERS}
>         ${MIDAS_DIR}/drivers/device/mscbdev
>         ${MIDAS_DIR}/mscb/src/mscb)
> 
> target_include_directories(sc_fe_mini PRIVATE ${DRV_DIR} ${MIDAS_DIR}/mscb/include ${MIDAS_DIR}/include)
> target_link_libraries(sc_fe_mini ${LIBS} ${MIDASLIB} ${FELIB} rt pthread util)
> 
> 
> 
> I seem to be able to compile the current midas distributions, including the scfe frontend
> 
> 
> 
> > To convert a MIDAS frontend to C++ follow this checklist:
> > 
> > a) add #include "mfe.h" after include of midas.h and fix all compilation errors.
> > 
> > NOTE: there should be no "extern C"  brackets around MIDAS include files.
> > 
> > NOTE: Expect to see following problems:
> > 
> > a1) duplicate or mismatched declarations of functions defined in mfe.h
> > a2) frontend_name and frontend_file_name should be "const char*" instead of "char*"
> > a3) duplicate "HNDLE hDB" collision with hDB from mfe.c - not sure why it worked before, either use HNDLE hDB from mfe.h or use "extern HNDLE hDB".
> > a4) poll_event() and interrupt_configure() have "source" as "int[]" instead of "int" (why did this work before?)
> > a5) use of "extern int frontend_index" instead of get_frontend_index() from mfe.h
> > a6) bk_create() last argument needs to be cast to (void**)
> > a7) "bool debug" collides with "debug" from mfe.h (why did this work before?)
> > 
> > b) remove no longer needed "extern C" brackets around mfe related code. Ideally there should be no "extern C" brackets anywhere.
> > 
> > c) in the Makefile, change CC=gcc to CC=g++ for compiling and linking everything as C++
> > 
> > c1) fix all compilation problems. most valid C code will compile as valid C++, but there is some known trouble:
> > - return value of malloc() & co needs to be cast to the correct data type: "char* s = (char*)malloc(...)"
> > - some C++ compilers complain about mismatch between signed and unsigned values
> > 
> > If you need help with converting your frontend from C to C++, I will be most happy
> > to assist you - post your compiler error messages to this forum or email them to me privately.
> > 
> > Good luck,
> > K.O.