title: MPI can not create parallel process, fails at MPI_INIT
body: <p>i am learning the MPI Interface for C and just installed MPI for my system (Mac Os Mojave 10.14.6). I made it with the help of this <a href="https://pdc.one/2017/04/21/Configure-OpenMP-&amp;-MPI-in-Clion-on-Mac/" rel="nofollow noreferrer">tutorial</a>.
  Everything was fine and now i wanted to start my first simple code.
  I tried to understand the error and searched for a solution, but could not find it on my own. Using CLion as IDE.
  <strong>main.c</strong></p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;mpi.h&gt;
  
  int main(argc, argv)
          int argc;
  
          char **argv;
  {
      int rank, size;
      MPI_Init( &amp;argc, &amp;argv );
      MPI_Comm_size(MPI_COMM_WORLD, &amp;size);
      MPI_Comm_rank(MPI_COMM_WORLD, &amp;size);
      printf("Hi from process %d of $d\n", rank, size);
      MPI_Finalize();
      return 0;
  }
  </code></pre>
  
  <p><strong>CMakeList.txt</strong></p>
  
  <pre><code>cmake_minimum_required(VERSION 3.15)
  project(uebung02 C)
  
  set(CMAKE_C_STANDARD 99)
  
  add_executable(uebung02 main.c)
  set(CMAKE_C_COMPILER /opt/openmpi/bin/mpicc)
  set(CMAKE_CXX_COMPILER /opt/openmpi/bin/mpic++)
  </code></pre>
  
  <p><strong>Error output</strong></p>
  
  <pre><code>/Users/admin/Documents/HU/VSuA/uebung02/cmake-build-debug/uebung02
  --------------------------------------------------------------------------
  PMIx has detected a temporary directory name that results
  It looks like orte_init failed for some reason; your parallel process is
  in a path that is too long for the Unix domain socket:
  likely to abort.  There are many reasons that a parallel process can
  fail during orte_init; some of which are due to configuration or
  environment problems.  This failure appears to be an internal failure;
  
  here's some additional information (which may only be relevant to an
  Open MPI developer):
      Temp dir: /var/folders/9j/54dxfbf1451dk82nn7y99d8r0000gn/T/openmpi-sessions-501@admins-MacBook-Pro_0/15653
  
  
    orte_ess_init failed
  Try setting your TMPDIR environmental variable to point to
  something shorter in length
  [admins-MacBook-Pro.local:44625] [[INVALID],INVALID] ORTE_ERROR_LOG: Unable to start a daemon on the local node in file ess_singleton_module.c at line 582
  [admins-MacBook-Pro.local:44625] [[INVALID],INVALID] ORTE_ERROR_LOG: Unable to start a daemon on the local node in file ess_singleton_module.c at line 166
    --&gt; Returned value Unable to start a daemon on the local node (-127) instead of ORTE_SUCCESS
  --------------------------------------------------------------------------
  --------------------------------------------------------------------------
  It looks like MPI_INIT failed for some reason; your parallel process is
  likely to abort.  There are many reasons that a parallel process can
  fail during MPI_INIT; some of which are due to configuration or environment
  problems.  This failure appears to be an internal failure; here's some
  [admins-MacBook-Pro.local:44625] *** An error occurred in MPI_Init
  addition[admins-MacBook-Pro.local:44625] *** on a NULL communicator
  [admins-MacBook-Pro.local:44625] *** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,
  [admins-MacBook-Pro.local:44625] ***    and potentially your MPI job)
  al information (which may only be relevant to an Open MPI
  developer):
  
  [admins-MacBook-Pro.local:44625] Local abort before MPI_INIT completed completed successfully, but am not able to aggregate error messages, and not able to guarantee that all other processes were killed!
    ompi_mpi_init: ompi_rte_init failed
    --&gt; Returned "Unable to start a daemon on the local node" (-127) instead of "Success" (0)
  --------------------------------------------------------------------------
  
  Process finished with exit code 1
  
  </code></pre>