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ortec++(1)                          OpenRTE                         ortec++(1)




NAME

       ortec++ -- OpenRTE C++ wrapper compiler


SYNTAX

       ortec++ [-showme|-showme:compile|-showme:link] ...


OPTIONS

       -showme
              Do  not  invoke the underlying compiler.  Instead, show the com-
              mand 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 exam-
              ple,  both "ortec++ --showme" and "ortec++ --showme my_source.c"
              will show all the wrapper-supplied flags.  But "ortec++  -showme
              -v" will only show the underlying compiler name and "-v".

       -showme:compile
              Do  not  invoke  the underlying C++ compiler.  Instead, show the
              compiler flags that would be supplied to the C++ compiler.

       -showme:link
              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 ortec++


DESCRIPTION

       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 OpenRTE programs, and then  invoke  the
       underlying compiler to actually perform the command.

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

   Background
       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:

       OPAL
           opalcc and opalc++

       ORTE
           ortecc and ortec++

       OMPI
           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 imple-
           mentations.

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

   Overview
       ortec++ is a convenience wrappers  for  the  underlying  C++  compiler.
       Translation  of an OpenRTE program requires the linkage of the OpenRTE-
       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.

       ortec++ passes its arguments to the underlying C++ compiler along  with
       the -I, -L and -l options required by OpenRTE programs.

       The  OpenRTE  Team  strongly  encourages  using  the  wrapper compilers
       instead of attempting to link to the OpenRTE libraries manually.   This
       allows the specific implementation of OpenRTE 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
       OpenRTE was configured and built; the values can change between differ-
       ent installations of the same version of OpenRTE.

       Indeed, since the wrappers are simply thin shells on top of an underly-
       ing compiler, there are very, very few compelling reasons  not  to  use
       ortec++.   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


NOTES

       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 dif-
       ferent 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:

         https://svn.open-mpi.org/trac/ompi/wiki/compilerwrapper3264


FILES

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

       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
       line.


ENVIRONMENT VARIABLES

       By  default,  the  wrappers  use  the compilers that were selected when
       OpenRTE was configured.  These compilers were  either  found  automati-
       cally 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 sec-
       tion), or  by  setting  selected  environment  variables  of  the  form
       "ORTE_value".

       Valid value names are:

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

       LDFLAGS
              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

       CXXFLAGS
              C++ compiler flags

       F77    Fortran 77 compiler

       FFLAGS Fortran 77 compiler flags

       FC     Fortran 90 compiler

       FCFLAGS
              Fortran 90 compiler flags



ORTE                                OpenRTE                         ortec++(1)

ortec++ 1.2.7 - Generated Sat Sep 13 08:07:56 CDT 2008
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