macOS Debugging a command line tool

[wlh99]

I have written a command line tool that takes input from STDIN, does stuff with it, and outputs it to STDOUT. It is run from the shell like:

$ mytool < inputfile.txt > outputfile.txt

Is there a way to run it like that in Xcode / instruments? The tool ussually works fine but with some input will crash with a segmentation fault.

 

[Hansr]

You can set the arguments being passed in for the project in Xcode and run it from within Xcode to debug.

But mainly it's just a point to add some measure to validate that the input is valid otherwise throw an error and notify the use and then exist gracefully or request new input.

 

[willieva]

If you're running on the command line then you can use gdb to debug it. Recompile with the -g flag and if a core file is generated when it seg faults then you can run gdb on the core file, or just run gdb on the executable.

But before you go learn a debugger, learn to use output judiciously. A few well chosen prints with the right info is extremely helpful when debugging. And make sure whatever print statement you're using actually gets written in case of a seg fault. Some print statements are buffered and won't get written.

BTW, I'm assuming you're compiling with gcc or g++. That sort of info is helpful when asking computer questions.