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I have a program and I am trying to debug it using gdb. Inside the program I have methods that require the user to enter an input using stdin. How can I enter this input when I am in gdb? So that I can trace how my methods work?

Ciro Santilli OurBigBook.com
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FranXh
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  • For the simpler case of direct input, the question is the same as this: http://stackoverflow.com/questions/455544 There are however cases which this does not cover: 1) you need to see stdout to decide stdin 2) actual timing and keypresses are needed like in ncurses. In those cases, maybe expect might do it: http://stackoverflow.com/questions/5579901/automated-test-tools-for-linux-ncurses – Ciro Santilli OurBigBook.com Jun 10 '15 at 17:48

3 Answers3

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$ cat >foo <<EOF
something
EOF
$ gdb -quiet /bin/cat
Reading symbols from /bin/cat...(no debugging symbols found)...done.
Missing separate debuginfos, use: debuginfo-install coreutils-8.12-7.fc16.x86_64
(gdb) run <foo
Starting program: /bin/cat <foo
something
[Inferior 1 (process 22436) exited normally]
(gdb)
matt
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8

You can also run your program first, then attach GDB to it:

gdb --pid $(pgrep your_program)

This way you will be able to run your program interactively in a separate terminal.

Hedede
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3

I just went through something like this yesterday and recursed through a bunch of "help" commands in gdb because I couldn't find exactly what I needed on the Internet.

I used set variable *your_variable* = *your desired input* after I had started gdb and began running my code. Worked like a charm.

I know this is late, but maybe it'll help someone else.

BWONG
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