http://www.gnu.org/software/libtool/manual/html_node/Debugging-executables.html

3.4 Debugging executables

Ifhellwas a complicated program, you would certainly want to test and debug it before installing it on your system. In the above section, you saw how the libtool wrapper script makes it possible to run the program directly, but unfortunately, this mechanism interferes with the debugger:

burger$ gdb hell     GDB is free software and you are welcome to distribute copies of it      under certain conditions; type "show copying" to see the conditions.     There is no warranty for GDB; type "show warranty" for details.     GDB 4.16 (i386-unknown-netbsd), (C) 1996 Free Software Foundation, Inc.          "hell": not in executable format: File format not recognized          (gdb) quit     burger$

Sad. It doesn't work because GDB doesn't know where the executable lives. So, let's try again, by invoking GDB directly on the executable:

burger$ gdb .libs/hell     GNU gdb 5.3 (i386-unknown-netbsd)     Copyright 2002 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 no warranty for GDB.  Type "show warranty" for details.     (gdb) break main     Breakpoint 1 at 0x8048547: file main.c, line 29.     (gdb) run     Starting program: /home/src/libtool/demo/.libs/hell     /home/src/libtool/demo/.libs/hell: can't load library 'libhello.so.0'          Program exited with code 020.     (gdb) quit     burger$

Argh. Now GDB complains because it cannot find the shared library thathellis linked against. So, we must use libtool in order to properly set the library path and run the debugger. Fortunately, we can forget all about the.libsdirectory, and just run it on the executable wrapper (see ):

burger$ libtool --mode=execute gdb hell     GNU gdb 5.3 (i386-unknown-netbsd)     Copyright 2002 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 no warranty for GDB.  Type "show warranty" for details.     (gdb) break main     Breakpoint 1 at 0x8048547: file main.c, line 29.     (gdb) run     Starting program: /home/src/libtool/demo/.libs/hell          Breakpoint 1, main (argc=1, argv=0xbffffc40) at main.c:29     29        printf ("Welcome to GNU Hell!\n");     (gdb) quit     The program is running.  Quit anyway (and kill it)? (y or n) y     burger$