g77.info: Debugging Options

Options for Debugging Your Program or GNU Fortran

   GNU Fortran has various special options that are used for debugging
either your program or `g77'

`-g'
     Produce debugging information in the operating system's native
     format (stabs, COFF, XCOFF, or DWARF).  GDB can work with this
     debugging information.

     A sample debugging session looks like this (note the use of the
     breakpoint):
          $ cat gdb.f
                PROGRAM PROG
                DIMENSION A(10)
                DATA A /1.,2.,3.,4.,5.,6.,7.,8.,9.,10./
                A(5) = 4.
                PRINT*,A
                END
          $ g77 -g -O gdb.f
          $ gdb a.out
          ...
          (gdb) break MAIN__
          Breakpoint 1 at 0x8048e96: file gdb.f, line 4.
          (gdb) run
          Starting program: /home/toon/g77-bugs/./a.out
          Breakpoint 1, MAIN__ () at gdb.f:4
          4             A(5) = 4.
          Current language:  auto; currently fortran
          (gdb) print a(5)
          $1 = 5
          (gdb) step
          5             PRINT*,A
          (gdb) print a(5)
          $2 = 4
          ...
     One could also add the setting of the breakpoint and the first run
     command to the file `.gdbinit' in the current directory, to
     simplify the debugging session.

   *Note Options for Debugging Your Program or GCC: (gcc)Debugging
Options, for more information on debugging options.