[Bug fortran/89039] New: Logical read from stream file that is neither 0 nor 1

albandil at atlas dot cz gcc-bugzilla@gcc.gnu.org
Thu Jan 24 15:07:00 GMT 2019


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89039

            Bug ID: 89039
           Summary: Logical read from stream file that is neither 0 nor 1
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: albandil at atlas dot cz
  Target Milestone: ---

Related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22495

Logicals read from an unformatted stream file that are neither 0 nor 1 behave
like this:

    print *, b, .not. b

    T T

i.e., both they and their negations evaluate to .true.

This reduces portability of stream files. For example, ifort uses -1 as .true.,
but when such stream files are read by gfortran, the nonzero value is not
converted to gfortran's .true.

(Maybe there is nothing that requires it, I don't know.)


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