One reason that I keep silverfrost's f95 suite around is that if I can get a program to compile, I can step through it with a debugger that I invoke on one of the pull-downs. I'd like to emulate this capability with gcc's gdb.
I googled for "gfortran debugger" and found a lot of information that was often more relevant to the linux crowd. I *did* find this from a previous exchange with FX:
> I read all the time about gfortran and gdb questions that seem to get > solid answers. I believe they are available for linux.
OK then, a brief summary: gfortran is the GNU Fortran compiler, part of GCC (the GNU Compiler Collection). GCC happens to be the system compiler on Linux and most other free software operating systems, which means it's widely used on these OS. gdb is the GNU debugger, also the default debugger on Linux and other free software OS.
But that doesn't mean it's restricted to Linux. Both GCC (and gfortran) and gdb are known to work on (free|net|open)bsd, Solaris, MacOS X, Windows, AIX, Irix, HP-UX, Tru64 and probably others.
!end excerpt
I can't quite seem to get out of the starting blocks on this one, and it's becoming more relevant as the programs one wants to step through have more f03 than ever. I tried "gdb [executable name]" and didn't get a bite on the command line. Is this perhaps addressed in gfortran.pdf?
I tried "gdb [executable name]" and didn't get a bite on the command
> line. Is this perhaps addressed in gfortran.pdf?
The documentation for gdb is the gdb doc, but I don't include it in the Windows distribution of gfortran I build. You can find it online, however: http://sourceware.org/gdb/documentation/
As for your problem, well, as you don't say what happens, it's hard to debug. I should work, as far as I can tell (see below for an example debugging session). If it's the command line you don't know, here's a short primer to get your started:
b myfile.f90:line -- sets a breakpoint at a given line in myfile.f90 r -- runs the program from the start c -- continue until the next breakpoint p myvariable -- display the content of a given variable n -- advance to next source line in that procedure s (or "step") -- advance to next statement, possibly entering into a subroutine or function (while with "n", you'll never follow a function call) q -- quit the debugger
There also are programs that provide a visual interface to gdb, but I've never used them much (apart from DDD, but I don't thing it's easy to install on Windows).
$ cat a.f90 program abstest complex c
c = ( 1.7951958020513104220, 2.6457513110645905904 ) write(*,*) abs(c) end program abstest
$ ./gfortran/bin/gfortran.exe -g a.f90
$ gdb a.exe GNU gdb 6.6 Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-mingw32"... (gdb) b a.f90:5 Breakpoint 1 at 0x40136d: file a.f90, line 5. (gdb) r Starting program: C:\msys\1.0.10\home\FX\irun/a.exe Loaded symbols for C:\WINDOWS\system32\ntdll.dll Loaded symbols for C:\WINDOWS\system32\kernel32.dll Loaded symbols for C:\WINDOWS\system32\msvcrt.dll
Breakpoint 1, abstest () at a.f90:5 5 write(*,*) abs(c) Current language: auto; currently fortran (gdb) p c $1 = (1.79519582,2.64575124) (gdb) c Continuing. 3.1973000
On Fri, 16 May 2008 11:31:09 +0000 (UTC), FX wrote: > I tried "gdb [executable name]" and didn't get a bite on the command >> line. Is this perhaps addressed in gfortran.pdf?
> The documentation for gdb is the gdb doc, but I don't include it in the > Windows distribution of gfortran I build. You can find it online, > however: http://sourceware.org/gdb/documentation/
> As for your problem, well, as you don't say what happens, it's hard to > debug. I should work, as far as I can tell (see below for an example > debugging session). If it's the command line you don't know, here's a > short primer to get your started:
> b myfile.f90:line -- sets a breakpoint at a given line in myfile.f90 > r -- runs the program from the start > c -- continue until the next breakpoint > p myvariable -- display the content of a given variable > n -- advance to next source line in that procedure > s (or "step") -- advance to next statement, possibly entering into > a subroutine or function (while with "n", you'll > never follow a function call) > q -- quit the debugger
> There also are programs that provide a visual interface to gdb, but I've > never used them much (apart from DDD, but I don't thing it's easy to > install on Windows).
> $ cat a.f90 > program abstest > complex c
> c = ( 1.7951958020513104220, 2.6457513110645905904 ) > write(*,*) abs(c) > end program abstest
> $ ./gfortran/bin/gfortran.exe -g a.f90
> $ gdb a.exe > GNU gdb 6.6 > Copyright (C) 2006 Free Software Foundation, Inc. > GDB is free software, covered by the GNU General Public License, and you are > welcome to change it and/or distribute copies of it under certain conditions. > Type "show copying" to see the conditions. > There is absolutely no warranty for GDB. Type "show warranty" for details. > This GDB was configured as "i686-pc-mingw32"... > (gdb) b a.f90:5 > Breakpoint 1 at 0x40136d: file a.f90, line 5. > (gdb) r > Starting program: C:\msys\1.0.10\home\FX\irun/a.exe > Loaded symbols for C:\WINDOWS\system32\ntdll.dll > Loaded symbols for C:\WINDOWS\system32\kernel32.dll > Loaded symbols for C:\WINDOWS\system32\msvcrt.dll
> Breakpoint 1, abstest () at a.f90:5 > 5 write(*,*) abs(c) > Current language: auto; currently fortran > (gdb) p c > $1 = (1.79519582,2.64575124) > (gdb) c > Continuing. > 3.1973000
> Program exited normally. > (gdb) quit
Thanks, FX, that will get me started. In that old thread that I dug up, there was apparently some talk of whether gdb could access specific values in an array. I'll see what happens when I step through James' sort_row program.
I don't have a "problem" other than that I've only used debuggers from IDE's. Since gdb seems to be joined to the hip with gfortran, it might merit an addition to gfortran.pdf. -- Ron Ford
> I don't have a "problem" other than that I've only used debuggers from > IDE's. Since gdb seems to be joined to the hip with gfortran, it might > merit an addition to gfortran.pdf.
Already for some time now I am trying to get a working installation of Photran and my compiler (I use g95, but that's irrelevant) plus other utilities (automatic generation of makefiles with sources in order of dependence). This is an IDE for your fortran-compiler (e.g. gfortran) together with your debugger (e.g. gdb), with capabilities beyond belief! Only problem is that it is all a bit complex to install. But there are many factsheets with info on this, so if you want to give it a try... And if you succeed, let me know!
On Fri, 16 May 2008 11:31:09 +0000 (UTC), FX wrote: > The documentation for gdb is the gdb doc, but I don't include it in the > Windows distribution of gfortran I build. You can find it online, > however: http://sourceware.org/gdb/documentation/
I've been looking through the information at this link today. Is this possibly true:
12.4.3 Fortran
GDB can be used to debug programs written in Fortran, but it currently supports only the features of Fortran 77 language.
On Sat, 17 May 2008 10:50:19 -0700 (PDT), Arjan wrote: >> I don't have a "problem" other than that I've only used debuggers from >> IDE's. Since gdb seems to be joined to the hip with gfortran, it might >> merit an addition to gfortran.pdf.
> Already for some time now I am trying to get a working installation of > Photran and my compiler (I use g95, but that's irrelevant) plus other > utilities (automatic generation of makefiles with sources in order of > dependence). This is an IDE for your fortran-compiler (e.g. gfortran) > together with your debugger (e.g. gdb), with capabilities beyond > belief! Only problem is that it is all a bit complex to install. But > there are many factsheets with info on this, so if you want to give it > a try... And if you succeed, let me know!
I think it's revealing about my character that I just get more excited when something is described as "probably a fool's errand." :-) What about this IDE? Can it work with gdb on win32 xp?
I'm not sure what others expect from a debugger. From the tips that display when I fire up silverforst's sdgb.exe, I see that I only use a small part of its functionality. For buttons, one displays variables, three deal with the stack, and two deal with "stepping:" in or over.
What I typically do is step over everything in the road until I see the value of the variable I'm keyed on. Another thing I do is step through new progs so as to see how it runs. I can't always *see* what a program does without ... seeing. -- Ron Ford "Moxie, a twelve-pound canine, visited unexpectedly yesterday. Since I was dog-sitting, I used the time to fix the face of a slat-wooden gate whence she might elope. I then repaired the jamb with a dutchman."
