Question

The main subroutine in the C sudoku game project returns different error codes according to what type of error happened during execution. For example:

int main(int argc, char** argv)
{
// Process argc and argv, configuring the game accordingly.
if (! processArgs(argc, argv)) {
fprintf(stderr, "Usage: game -debug | -normal | -hard");
return 1;
}
// Load graphics
if (! loadGraphics()) {
fprintf(stderr, LINE_FILE"\nERROR: Failed to load pdcurses.");
return 2;
}
// Generate the board
if (! loadboard()) {
fprintf(stderr, LINE_FILE"\nERROR: Could not generate "
}
}

Answer 1

return 3;

/* More stuff... */

// End.
printf("Have a nice day!");
return 0;
}

Answer 2

The question is, is it okay to do this (returning numbers different from 0 if something wrong happens during execution to 'crash' the game while leaving me with a relatively meaningful error message) or do the different return values in main have some semantic value to the OS besides "something went wrong in the program" ?

Answer 3

oh and LINE_FILE is just a macro to print the line number where the error occured.

Answer 4

Generally speaking, return values other than 0 (which is typically interpreted to mean “success”) are program-specific. There's some additional work from the operating system to set a high bit of an 8-bit return code in cases of abnormal termination.

More at http://stackoverflow.com/questions/1101957/are-there-any-standard-exit-status-codes-in-linux .