Command Line C program to Swift

Question

I have source code of a command line C game, that waits for user's stdin, and outputs stdout. I want to give input from a text field through to the main of this C code and take the output in a text area field for example.

int mainer(int argc, char **argv) {
    int i;
    int hitme;
    char ch;
    prelim();

    if (argc > 1) { // look for -f option
        if (strcmp(argv[1], "-f")== 0) {
            coordfixed = 1;
            argc--;
            argv++;
        }
    }


    if (argc > 1) {
        fromcommandline = 1;
        line[0] = '\0';
        while (--argc > 0) {
            strcat(line, *(++argv));
            strcat(line, " ");
        }
    }
    else fromcommandline = 0;
 // some other code

}

From the example here, I should do the following:

let args = [" ", "regular", "short", ""]

var cargs = args.map { strdup($0) }
let result = mainer(Int32(args.count), &cargs)
for ptr in cargs { free(ptr) }

How could I call the main function, and keep it alive and keep giving to it arguments to make it act as command line.

Answer 1

I would set up your app with a TextArea and a TextField, and provide alternatives to printf and scanf that either add text to the text area or get sent text from the textfield (maybe with an "Enter" UIButton). Then you can compile the C code and call it from Swift. Objective C is actually C way under the covers, so you should be able to to get this to run with just a little alteration.

In order to get the code to run you'll probably have to make this code run in it's own thread, and jump through some hoops to get those calls to behave correctly, but it should be doable.