How to load program reading stdin and taking parameters in gdb?
EmacsGdbRedirectCommand Line-ArgumentsEmacs Problem Overview
> I have a program that takes input from > stdin and also takes some parameters > from command line. It looks like this: > > cat input.txt > myprogram -path "/home/user/work" > > I try to debug the code with gdb > inside emacs, by M-x gdb, I try to > load the program with the command: > > gdb cat input.txt > myprogram -path "/home/user/work" > > However, gdb does not like it.
Question cribbed from here.
Unfortunately I don't understand the solution and am not sure what to do beyond compiling with the -g
option and running the command M-x gdb.
Emacs Solutions
Solution 1 - Emacs
If you were doing it from a shell you'd do it like this:
% gdb myprogram
gdb> run params ... < input.txt
This seems to work within emacs too.
Solution 2 - Emacs
There are several ways to do it:
$ gdb myprogram
(gdb) r -path /home/user/work < input.txt
or
$ gdb myprogram
(gdb) set args -path /home/user/work < input.txt
(gdb) r
or
$ gdb -ex 'set args -path /home/user/work < input.txt' myprogram
(gdb) r
where the gdb run
command (r
) uses by default the arguments as set previously with set args
.
Solution 3 - Emacs
For completeness' sake upon starting a debugging session there is also the --args option. ie)
gdb gdbarg1 gdbarg2 --args yourprog arg1 arg2 -x arg3
Solution 4 - Emacs
This is eleven years later, and this question has an answer already, but for someone just like me in the future, I just wanted to add some thing.
After you run gdb your_program
, if you just type run < file_containing_input
, the program will just run till the end, and you might not catch the problem, so before you do run < file_containing_input
do a break. Something like this
$ gdb your_program
gdb> break main
gdb> run < file_containing_input
Solution 5 - Emacs
And if you do not need to debug from the very beginning you can also attach to an already running process by using:
$ gdb myprogram xxx
where xxx is the process id. Then you do not need to tell gdb the starting arguments.