Question

I have an mpi program and managed to compile and link it via Xcode 4.
Now I want to debug it using Xcode 4.

How can I pipe the standard input to the program from a file?

In terminal I would type

mpirun -np 2 program < input.txt

I am able to run the program defining a custom executable (mpirun) in the “Info” panel of the Scheme editor, I also know that I can pass arguments in the “Arguments” panel. But Xcode 4 does not seem to accept “< input.txt” as an argument, even if I check “Use custom working directory” + add the correct directory of the input script in the “Options” panel.

This article Says it is possible to use “< input.txt” as an argument, but I guess that worked in Xcode 2 or Xcode 3, but it does not seem to work in Xcode 4 anymore.

Answer 1

In Xcode 4.5.1:

1. Open the scheme editor (Product menu -> Edit Scheme…)
2. Select the Run Debug scheme
3. In the ‘Info’ tab panel, change the ‘Launch’ radio button selection from ‘Automatically’ to ‘Wait for MyApp.app to launch’
4. Close the scheme editor
5. Press the Run button to build and run your target. (Xcode’s status window in the toolbar will show ‘Waiting for MyApp to launch’)
6. Launch Terminal and cd to your built application’s folder. (It will be something like /Users/user/Library/Developer/Xcode/DerivedData/MyApp-dmzfrqdevydjuqbexdivolfeujsj/Build/Products/Debug / )

7. Launch your app piping in whatever you want into standard input:

   echo mydata | ./MyApp.app/Contents/MacOs/MyApp
   

8. Switch back to Xcode and the debugger will have detected your application’s launch and attached to it.