Return value from Objective C Procedure

Hi Guys,

hopefully you can help me, I have created a procedure in Objective C for iOS whereby i pass a string to the procedure and it replaces the ' character with a blank space. This is my code as below:

void REPLACE_CHARACTERS(NSString* ORIG)
{
NSString *str = ORIG;
str = [str stringByReplacingOccurrencesOfString:@"'" withString:@" "];
return str
}

How do i use the 'str' value back in my main project? it doesn't appear i can assign the returned value to a global variable.

Any help is appreciated,

Many thanks

Ben