gdb dies debugging fortran program

L Anderson lowella@mvseac.com
Sun Aug 12 22:47:00 GMT 2012


Christopher Faylor wrote:
> 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.
>
Running under mintty--haven't used windows console for cygwin in ages.

LA


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