# CMAQ5.3 CCTM undefined reference error **URL:** \ **Category:** Compiling\ **Created:** [October 3, 2019, 3:00pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997 "2019-10-03T15:00:25Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![jliu](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@jliu](https://forum.cmascenter.org/u/jliu)\ **Post date:** [October 3, 2019, 3:00pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/1 "2019-10-03T15:00:25Z")
Hello, Any one has any suggestions on the compiling errors below: Many thanks! I used the gcc version 8.3.0; netcdf-c-4.6.0; netcdf-fortran-4.5.0; mpich-3.3.1; ioapi-3.2; no errors on icon, bcon ad micp * * * distr\_env.o: In function `distr\_env\_’: distr\_env.c:(.text+0xc0): undefined reference to `ompi\_mpi\_comm\_world’ distr\_env.c:(.text+0xc7): undefined reference to `ompi\_mpi\_int’ distr\_env.c:(.text+0xe1): undefined reference to `ompi\_mpi\_char’ distr\_env.c:(.text+0xe7): undefined reference to `ompi\_mpi\_comm\_world’ distr\_env.c:(.text+0xf4): undefined reference to `ompi\_mpi\_comm\_world’ distr\_env.c:(.text+0x112): undefined reference to `ompi\_mpi\_comm\_world’ distr\_env.c:(.text+0x119): undefined reference to `ompi\_mpi\_int’ distr\_env.c:(.text+0x13b): undefined reference to `ompi\_mpi\_char’ distr\_env.c:(.text+0x141): undefined reference to `ompi\_mpi\_comm\_world’ collect2: error: ld returned 1 exit status make: \*\*\* [CCTM\_v53.exe] Error 1 * * * ---
**Author:** ![cjcoats](https://avatars.discourse-cdn.com/v4/letter/c/ac8455/32.png) [@cjcoats](https://forum.cmascenter.org/u/cjcoats)\ **Post date:** [October 3, 2019, 3:07pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/2 "2019-10-03T15:07:14Z")
This looks like something in the build was done with _OpenMPI_ instead of _mpich_ – as a diagnostic, go to the directory for your MPI library and do `nm lib`. MPICH symbols have all-caps `MPI` in their prefixes; oOpenMPI ones have `ompi_`. ---
**Author:** ![jliu](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@jliu](https://forum.cmascenter.org/u/jliu)\ **Post date:** [October 3, 2019, 3:37pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/3 "2019-10-03T15:37:12Z")
I did not find any “ompi\_” in MPI lib. “something in the build was done with \*OpenMPI”, which means that the CMAQ modules are builded by “openmpi” or others, such as ioapi? Any suggestion to fixed it? switch to openmpi? ---
**Author:** ![cjcoats](https://avatars.discourse-cdn.com/v4/letter/c/ac8455/32.png) [@cjcoats](https://forum.cmascenter.org/u/cjcoats)\ **Post date:** [October 3, 2019, 3:51pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/4 "2019-10-03T15:51:06Z")
It looks, in particular, as though _distr\_env.c_ was compiled with an OpenMPI _mpicc_, not with the corresponding MPICH _mpicc_. Try removing it (and maybe all the _.o_ files) and re-building. ---
**Author:** ![rodrigo](https://avatars.discourse-cdn.com/v4/letter/r/4af34b/32.png) [@rodrigo](https://forum.cmascenter.org/u/rodrigo)\ **Post date:** [December 3, 2019, 12:14pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/5 "2019-12-03T12:14:05Z")
I need help with the same problem, did anyone get a solution? ---
**Author:** ![lizadams](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@lizadams](https://forum.cmascenter.org/u/lizadams)\ **Post date:** [December 4, 2019, 10:00pm UTC](https://forum.cmascenter.org/t/cmaq5-3-cctm-undefined-reference-error/997/6 "2019-12-04T22:00:32Z")
Please try following one of the tutorials that are available >