Question

I am trying to create a method to quickly and easily create an NSArray from a va_list, however, when I run the method, I receive an exc_bad_access due to some bad memory management somewhere, although I cannot determine where this place is.

Please could you take a look at the code and tell me where and why this is occurring.

Thanks in advanced,

Max.

NSArray *arrayCreate(id firstObject, ...) {
    NSMutableArray *objects = [NSMutableArray array];
    [objects addObject:firstObject];
    va_list args;
    va_start(args, firstObject);
    id arg;
    while ((arg = va_arg(args, id))) {
        [objects addObject:arg];
    }
    va_end(args);
    return [objects copy];
}

Usage (just to test that it’s working):

NSLog(@"%@", arrayCreate(@"1", @"2", @"3", @"4"));

Answer 1

You forgot to nil-terminate your arglist. In C, functions have no way of knowing how many variadic arguments you passed, so it’s common to end a series of pointers with a null pointer (to indicate no more valid input.) Your code appears to be checking for this (arg = va_arg(args, id) will be false when it reaches nil) but your input is missing it.