Gets an environmental variable, broadcasts to all processors in communicator from MPI rank zero


PetscErrorCode PetscOptionsGetenv(MPI_Comm comm, const char name[], char env[], size_t len, PetscBool *flag)


Input Parameters#

  • comm - communicator to share variable

  • name - name of environmental variable

  • len - amount of space allocated to hold variable

Output Parameters#

  • flag - if not NULL indicates if the variable was found

  • env - value of variable


You can also “set” the environmental variable by setting the options database value -name “stringvalue” (with name in lower case). If name begins with PETSC_ this is discarded before checking the database. For example, PETSC_VIEWER_SOCKET_PORT would be given as -viewer_socket_port 9000

If comm does not contain the 0th process in the MPI_COMM_WORLD it is likely on many systems that the environmental variable will not be set unless you put it in a universal location like a .chsrc file





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