In the interest of clean compiles, a warning about an unused variable is welcome. However, should you have a situation that calls for leaving an unused variable in the code, keep reading.
One example where I’ve found this handy is when I have a variable that is a placeholder for something that has yet to be implemented.
Here is how a typical warning looks for an unused variable.
To suppress the warning, add a #pragma as follows:
NSString *tempMsg; #pragma unused (tempMsg)
The output in Xcode now looks as follows, notice there are no warnings:
You can add more than one variable to the #pragma statement as follows:
NSString *tempMsg; int flag = 0; char *ptr; #pragma unused (tempMsg, flag, ptr)
One reason I find this approach helpful versus commenting out a variable(s), is that I can do a project search for “unused” and get a quick glimpse of code that I need to revisit.