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(g77-295.info)Compilers Other Than f2c

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Compilers Other Than `f2c'
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   On systems with Fortran compilers other than `f2c' and `g77', code
compiled by `g77' is not expected to work well with code compiled by
the native compiler.  (This is true for `f2c'-compiled objects as well.)
Libraries compiled with the native compiler probably will have to be
recompiled with `g77' to be used with `g77'-compiled code.

   Reasons for such incompatibilities include:

   * There might be differences in the way names of Fortran procedures
     are translated for use in the system's object-file format.  For
     example, the statement `CALL FOO' might be compiled by `g77' to
     call a procedure the linker `ld' sees given the name `_foo_',
     while the apparently corresponding statement `SUBROUTINE FOO'
     might be compiled by the native compiler to define the
     linker-visible name `_foo', or `_FOO_', and so on.

   * There might be subtle type mismatches which cause subroutine
     arguments and function return values to get corrupted.

     This is why simply getting `g77' to transform procedure names the
     same way a native compiler does is not usually a good idea--unless
     some effort has been made to ensure that, aside from the way the
     two compilers transform procedure names, everything else about the
     way they generate code for procedure interfaces is identical.

   * Native compilers use libraries of private I/O routines which will
     not be available at link time unless you have the native
     compiler--and you would have to explicitly ask for them.

     For example, on the Sun you would have to add `-L/usr/lang/SCx.x
     -lF77 -lV77' to the link command.