www.delorie.com/gnu/docs/gcc/g77_357.html   search  
 
Buy the book!


Using and Porting GNU Fortran

[ < ] [ > ]   [ << ] [ Up ] [ >> ]         [Top] [Contents] [Index] [ ? ]

9.6.2 Meaning of Exclamation Point in Column 6

g77 treats an exclamation point (`!') in column 6 of a fixed-form source file as a continuation character rather than as the beginning of a comment (as it does in any other column) when the `-fvxt' option is specified.

The following program, when run, prints a message indicating whether it is interpreted according to GNU Fortran (and Fortran 90) rules or VXT Fortran rules:

 
C234567  (This line begins in column 1.)
      I = 0
     !1
      IF (I.EQ.0) PRINT *, ' I am a VXT Fortran program'
      IF (I.EQ.1) PRINT *, ' I am a Fortran 90 program'
      IF (I.LT.0 .OR. I.GT.1) PRINT *, ' I am a HAL 9000 computer'
      END

(In the GNU Fortran and Fortran 90 languages, exclamation point is a valid character and, unlike space (SPC) or zero (`0'), marks a line as a continuation line when it appears in column 6.)


  webmaster     delorie software   privacy  
  Copyright 2003   by The Free Software Foundation     Updated Jun 2003