www.delorie.com/gnu/docs/gcc/g77_555.html   search  
 
Buy the book!


Using and Porting GNU Fortran

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

14.4.2 Variables Assumed To Be Zero

Many Fortran programs were developed on systems that provided automatic initialization of all, or some, variables and arrays to zero. As a result, many of these programs depend, sometimes inadvertently, on this behavior, though to do so violates the Fortran standards.

You can ask g77 for this behavior by specifying the `-finit-local-zero' option when compiling Fortran code. (You might want to specify `-fno-automatic' as well, to avoid code-size inflation for non-optimized compilations.)

Note that a program that works better when compiled with the `-finit-local-zero' option is almost certainly depending on a particular system's, or compiler's, tendency to initialize some variables to zero. It might be worthwhile finding such cases and fixing them, using techniques such as compiling with the `-O -Wuninitialized' options using g77.


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