Is there a way to have xcode 5 run a command line tool program with a file that the program can pull data from to use in a cin or scanf function? I'm thinking of what can be done in the command line when once a program is compiled you can have run "myfile <infile.txt" and your program will run taking input data from infile.txt rather than the keyboard.
All command line tools by by the nature of Unix can do that. They don;t care where stdin comes from, keyboard, file redirect or pipe.
Or am I misunderstanding what you are asking?
Yes, but I want to do it from within xcode when testing little C and C++ programs for a programming class.
So what's the problem?
When you exec a command line program it behaves just as it does when run from the command line. It will still read stdin and it doesn;t care where the input is coming from.
I would like it to take input from a file rather than the keyboard. Is there a place to specify that file so when I click run it will take the file input rather than the keyboard input?
You want what to take input from a file, a program running on the command line, then
# program < file
If you want to do this from inside another program; you first create the child process, open the file you want read on stdin, then use dup2() to duplicate the descriptor on fd 0 (stdin) and then exec the program
More then this and you'll have to show your code, what you have so far. I hate doing home work assignments 😉
#program <file
Yes exactly, but I don't want to use the command line. I am just writting c and c++ programs with the command line tool template in xcode and debugging, compiling, linking and running within xcode too. When I click run in xcode I want it to do #program <file and show me the out put right there in the Output box. I don't want to go back and fourth between a text editor (or xcode) and the command line.
You can do that in "Edit scheme" and adjust how your program is run. I think you could change the executable to a script that does what you need an executes the program in Xcode.
@etersoft, Wasn't sure what to do in there. Would that be a post run action or pre run. Then would I just use "</infile.txt " for the sricpt? Is it ok to put the infile.txt in the same folder as main? Last time I did that and ran from the command line something weird happend. The program ran with the input.txt file but then main got overwritten with the input.txt file data. Guess I'll just try stuff. My command line skills are lacking but you don't get better if you don't try. Need to take a unix os class.🙂
Glad you jumped in.
I do seem to remember in Xcode 4 being able to, in the run scheme, add a file redirect to the arguments passed on launch.
But I've been trying what I think was what I did in 4, adding < file to the argument line and it's not working.
I tried quoting the string, giving absolute paths, but no matter what the program just sees it as a command line argument the file is not being redirected.
neither work. The first sees agrv 1 as the whole line the second sees argv 1 as <
So am I missing something? Did they change this in 5?
What you have to do is change your executable path to /bin/sh or something similar. It has to be an executable, not a script. You can then pass a script as an argument if you want. I just tried a little project with /bin/sh as my executable and my arguments passed on launch are:
/Users/jdaniel/bin/tester | $(TARGET_BUILD_DIR)/$(TARGET_NAME)
tester is a little script that echoes a line. Then that gets piped to my Xcode program. I could probably hack on that a bit to get it to expand shell variables like ~ so I wouldn't have to pass my home directory. It will expand Xcode environment variables. You would have to use those as the derived paths aren't easily guessed.
Ok, got it working with help from another forum. I think what I wanted to do was a little different. After setting the excuitable to /bin/sh in Edit Schemes I used the following argument and it worked:
-c "$(TARGET_BUILD_DIR)/$(TARGET_NAME) < /filepath/infile.txt"
Note in edit schemes to set the excuitable I had to use cmd+shft+g to get the goto drop down menu a then search for /bin/sh. Also the argument didn't like a long file path for the infile for some reason.
Thanks all for the help.
Adding a file to run with a command line tool
