Re: gdb dies debugging fortran program

[Christopher Faylor <cgf-use-the-mailinglist-please at cygwin dot com>]

On Sun, Aug 12, 2012 at 12:59:35PM -0700, L Anderson wrote:
>I trying to use gdb to debug a fortran program compiled with gfortran
>but gdb inconsistently dies in the process.  I have written a
>small fortran program that exhibits the problem.
>
>The test program is:
>
><code>
>       PROGRAM GDBDIES
>
>C     PROGRAM TO SHOW GDB DIES DEBUGGING IT
>       IMPLICIT INTEGER (A-Z)
>
>       A = 1
>
>       B = 2
>
>       IF (B.EQ.2) GOTO 20
>
>       C = 4
>
>    20 D = 200
>
>       END
></code>
>
>I compiled it with:
>
>$ gfortran -g -o gdbdies gdbdies.f
>
>and ran it under gdb thusly:
>
>$ gdb gdbdies.exe
>GNU gdb (GDB) 7.3.50.20111026-cvs (cygwin-special)
>Copyright (C) 2011 Free Software Foundation, Inc.
>License GPLv3+: GNU GPL version 3 or later 
><http://gnu.org/licenses/gpl.html>
>This is free software: you are free to change and redistribute it.
>There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
>and "show warranty" for details.
>This GDB was configured as "i686-cygwin".
>For bug reporting instructions, please see:
><http://www.gnu.org/software/gdb/bugs/>...
>Reading symbols from /cygdrive/m/Langpak/src/gdbdies.exe...done.
>(gdb) b 9
>Breakpoint 1 at 0x40117d: file gdbdies.f, line 9.
>(gdb) run
>Starting program: /cygdrive/m/Langpak/src/gdbdies.exe
>[New Thread 4672.0x1630]
>[New Thread 4672.0x15b8]
>
>Breakpoint 1, gdbdies () at gdbdies.f:9
>9             B = 2
>(gdb) n
>10            C = 3
>(gdb) n
>11            IF (C.EQ.3) GOTO 20
>(gdb) n    <<<---here's where it goes out to lunch and never comes back.
>
>gdb doesn't consistently die in the same place--it seems to be related
>to where the breakpoint is set.  However, it seems to more consistently
>die just after line 11 where the GOTO 20 is.
>
>My system is XP Pro SP3 with Cygwin DLL version 1.7.16
>
>
>Is this a bug in gdb or am I doing something wrong?

Are you running gdb under mintty or on a windows console.  I've seen a
problem with gdb running in a console which manifests the way you
describe.  Running under mintty usually works better.

cgf

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