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(g77-300.info)Compiler Options

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Compiler Options
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   `g77' offers compiler options that `f2c' doesn't, most of which are
designed to more easily accommodate legacy code:

   * Two that control the automatic appending of extra underscores to
     external names

   * One that allows dollar signs (`$') in symbol names

   * A variety that control acceptance of various "ugly" constructs

   * Several that specify acceptable use of upper and lower case in the
     source code

   * Many that enable, disable, delete, or hide groups of intrinsics

   * One to specify the length of fixed-form source lines (normally 72)

   * One to specify the the source code is written in Fortran-90-style
     free-form

   However, `f2c' offers a few that `g77' doesn't, like an option to
have `REAL' default to `REAL*8'.  It is expected that `g77' will offer
all of the missing options pertinent to being a Fortran compiler at
some time in the future.