On platforms where gdbserver is supported, it is possible to use this tool to debug your application remotely. This can be useful in situations where the program needs to be run on a target host that is different from the host used for development, particularly when the target has a limited amount of resources (either CPU and/or memory).
To do so, start your program using gdbserver on the target machine. gdbserver then automatically suspends the execution of your program at its entry point, waiting for a debugger to connect to it. The following commands starts an application and tells gdbserver to wait for a connection with the debugger on localhost port 4444.
$ gdbserver localhost:4444 program Process program created; pid = 5685 Listening on port 4444
Once gdbserver has started listening, we can tell the debugger to establish a connection with this gdbserver, and then start the same debugging session as if the program was being debugged on the same host, directly under the control of GDB.
$ gdb program (gdb) target remote targethost:4444 Remote debugging using targethost:4444 0x00007f29936d0af0 in ?? () from /lib64/ld-linux-x86-64.so. (gdb) b foo.adb:3 Breakpoint 1 at 0x401f0c: file foo.adb, line 3. (gdb) continue Continuing. Breakpoint 1, foo () at foo.adb:4 4 end foo;
It is also possible to use gdbserver to attach to an already running program, in which case the execution of that program is simply suspended until the connection between the debugger and gdbserver is established.
For more information on how to use gdbserver, see the `Using the gdbserver Program' section in Debugging with GDB. GNAT provides support for gdbserver on x86-linux, x86-windows and x86_64-linux.