cmake fortran undefined reference to MAIN__ on linux-Collection of common programming errors

2 years ago
admin
3 minutes

I trying to get a cmake build system working on linux. The project contains a bunch of executables and two libraries. One of the executables is first built as a library, then that library is linked with the object file containing the man subroutine. This was done because the rest of the executables depend on that library. The tricky part is that the main subroutine is defined inside a module that the rest of sources depend on so this needs to be compiled before the rest of the sources. The effect is that the main subroutine gets added to the resulting library. This seems to work fine on Mac OS X but, the linking state fails on Linux.

The cmake file for the failing part looks like

cmake_minimum_required (VERSION 2.8)

# Create an empty variable to hold all the source files.
set (vmec_sources "")

# Add subdirectory for all the sources.
add_subdirectory (Sources)

add_library (vmec STATIC ${vmec_sources})
add_dependencies (vmec stell)

# Define an executable and link all libraries.
add_executable (xvmec ${CMAKE_CURRENT_SOURCE_DIR}/Sources/General/vmec_main.f)
add_dependencies (xvmec vmec)
target_link_libraries (xvmec vmec stell)

if ((NOT ${NETCDF_C} STREQUAL "") AND (NOT ${NETCDF_F} STREQUAL ""))
    target_link_libraries (xvmec ${NETCDF_C} ${NETCDF_F})
endif ()

When running cmake, everything configures fine and generates a make file when I run make Mac OS X everything works fine. When I run make on Linux it fails.

The output from the make VERBOSE=1 On Linux produces

Linking Fortran executable ../build/bin/xvmec
cd /home/user/reconstruction/VMEC2000 && /usr/bin/cmake -E cmake_link_script CMakeFiles/xvmec.dir/link.txt --verbose=1
/usr/bin/gfortran      -cpp -D NETCDF -I /usr/include CMakeFiles/xvmec.dir/Sources/General/vmec_main.f.o  -o ../build/bin/xvmec -rdynamic ../build/lib/libvmec.a ../build/lib/libstell.a /usr/lib/libnetcdf.so /usr/lib/libnetcdff.so 
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/libgfortranbegin.a(fmain.o): In function `main':
(.text+0x26): undefined reference to `MAIN__'
collect2: ld returned 1 exit status
make[2]: *** [build/bin/xvmec] Error 1
make[2]: Leaving directory `/home/user/reconstruction'
make[1]: *** [VMEC2000/CMakeFiles/xvmec.dir/all] Error 2
make[1]: Leaving directory `/home/user/reconstruction'
make: *** [all] Error 2

On Mac OS X, I get

Linking Fortran executable ../build/bin/xvmec
cd /Users/user/repo/trunk/VMEC2000 && "/Applications/CMake 2.8-8.app/Contents/bin/cmake" -E cmake_link_script CMakeFiles/xvmec.dir/link.txt --verbose=1
/usr/local/bin/gfortran     -framework Accelerate   -cpp -D DARWIN -D NETCDF -I /Users/user/NetCDF/include -O3 -ftree-vectorize -m64 -march=native -fomit-frame-pointer -falign-functions -mfpmath=sse CMakeFiles/xvmec.dir/Sources/General/vmec_main.f.o  -o ../build/bin/xvmec  ../build/lib/libvmec.a ../build/lib/libstell.a /Users/user/NetCDF/lib/libnetcdf.dylib /Users/user/NetCDF/lib/libnetcdff.dylib 
"/Applications/CMake 2.8-8.app/Contents/bin/cmake" -E cmake_progress_report /Users/user/repo/trunk/CMakeFiles  100
[100%] Built target xvmec

The link line looks like it is linking all the same stuff in the correct order so I don’t understand why this is failing on Linux.

  1. Turns out I had the wrong file listed as containing the main method. It seems that later versions of gfortran can link ‘MAIN__’ from a inside a library while gfortran-4.4 cannot.

Originally posted 2013-11-09 23:21:21.