Provided by: libopenmpi-dev_1.4.1-2_i386 bug


       mpicc -- Open MPI C wrapper compiler


       mpicc [-showme|-showme:compile|-showme:link] ...


              Do  not  invoke  the  underlying  compiler.   Instead,  show the
              command line that would be  executed  to  compile  the  program.
              NOTE:  If a non-filename argument is passed on the command line,
              the -showme option will not display any additional  flags.   For
              example,  both "mpicc --showme" and "mpicc --showme my_source.c"
              will show all the wrapper-supplied flags.   But  "mpicc  -showme
              -v" will only show the underlying compiler name and "-v".

              Do  not  invoke  the  underlying  C compiler.  Instead, show the
              compiler flags that would be supplied to the C compiler.

              Do not invoke the underlying  C  compiler.   Instead,  show  the
              linker flags that would be supplied to the C compiler.

       See  the  man  page for your underlying compiler for other options that
       can be passed through mpicc


       Conceptually, the role of these commands is quite simple: transparently
       add  relevant compiler and linker flags to the user’s command line that
       are necessary to compile / link Open MPI programs, and then invoke  the
       underlying compiler to actually perform the command.

       As  such,  these  commands  are  frequently  referred  to  as "wrapper"
       compilers because they do not actually  compile  or  link  applications
       themselves; they only add in command line flags and invoke the back-end

       Open MPI is comprised of three software  layers:  OPAL  (Open  Portable
       Access  Layer),  ORTE (Open Run-Time Environment), and OMPI (Open MPI).
       There are wrapper compilers for each layer; each layer’s  wrapper  only
       links  in  the  libraries  relevant for that layer.  Specifically, each
       layer provides the following wrapper compilers:

           opalcc and opalc++

           ortecc and ortec++

           mpicc, mpic++, mpicxx, mpiCC (only on  systems  with  case-senstive
           file  systems),  mpif77, and mpif90.  Note that mpic++, mpicxx, and
           mpiCC all invoke the same underlying C++  compiler  with  the  same
           options.    All  are  provided  as  compatibility  with  other  MPI

       The Fortran wrapper compilers for  MPI  (mpif77  and  mpif90)  will  be
       inoperative  and will return an error on use if Fortran 77 / Fortran 90
       support was not built into the MPI layer.

       mpicc  is  a  convenience  wrappers  for  the  underlying  C  compiler.
       Translation  of  an  Open  MPI program requires the linkage of the Open
       MPI-specific libraries which may not reside  in  one  of  the  standard
       search  directories  of ld(1).  It also often requires the inclusion of
       header files what may also not be found in a standard location.

       mpicc passes its arguments to the underlying C compiler along with  the
       -I, -L and -l options required by Open MPI programs.

       The  Open  MPI  Team  strongly  encourages  using the wrapper compilers
       instead of attempting to link to the Open MPI libraries manually.  This
       allows  the  specific  implementation  of  Open  MPI  to change without
       forcing changes to linker directives in users’ Makefiles.  Indeed,  the
       specific  set  of  flags  and  libraries  used by the wrapper compilers
       depends on how Open MPI was configured and built; the values can change
       between different installations of the same version of Open MPI.

       Indeed,  since  the  wrappers  are  simply  thin  shells  on  top of an
       underlying compiler, there are very, very few compelling reasons not to
       use  mpicc.   When it is not possible to use the wrappers directly, the
       -showme:compile and -showme:link options should be  used  to  determine
       what flags the wrappers would have used.  For example:

       shell$ cc -c file1.c ‘mpicc -showme:compile‘

       shell$ cc -c file2.c ‘mpicc -showme:compile‘

       shell$ cc file1.o file2.o ‘mpicc -showme:link‘ -o my_mpi_program


       It is possible to make the wrapper compilers multi-lib aware.  That is,
       the libraries and includes specified may differ based on  the  compiler
       flags  specified  (for  example,  with  the  GNU  compilers on Linux, a
       different library path may be used if -m32 is seen  versus  -m64  being
       seen).   This  is not the default behavior in a standard build, but can
       be activated (for example, in a binary package providing both 32 and 64
       bit support).  More information can be found at:


       The  string  that  the  wrapper  compilers insert into the command line
       before invoking the underlying compiler  are  stored  in  a  text  file
       created  by  Open MPI and installed to $pkgdata/mpicc-wrapper-data.txt,
       where $pkgdata is typically $prefix/share/openmpi, and $prefix  is  the
       top installation directory of Open MPI.

       It  is  rarely  necessary  to edit this file, but it can be examined to
       gain insight into what flags the wrappers are placing  on  the  command


       By default, the wrappers use the compilers that were selected when Open
       MPI was configured.  These compilers were either found automatically by
       Open  MPI’s "configure" script, or were selected by the user in the CC,
       CXX, F77,  and/or  FC  environment  variables  before  "configure"  was
       invoked.   Additionally,  other  arguments specific to the compiler may
       have been selected by configure.

       These values can be selectively overridden by either editing  the  text
       files   containing   this  configuration  information  (see  the  FILES
       section), or by setting selected  environment  variables  of  the  form

       Valid value names are:

              Flags added when invoking the preprocessor (C or C++)

              Flags added when invoking the linker (C, C++, or Fortran)

       LIBS   Libraries added when invoking the linker (C, C++, or Fortran)

       CC     C compiler

       CFLAGS C compiler flags

       CXX    C++ compiler

              C++ compiler flags

       F77    Fortran 77 compiler

       FFLAGS Fortran 77 compiler flags

       FC     Fortran 90 compiler

              Fortran 90 compiler flags