Frequently used symbol “|” in Objective-C

Question

self.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleWidth;

The source code is shown above. Wonder what the symbol \"|

Answer 1

| is the bitwise OR operator in C (and therefore in Objective-C).

See http://en.m.wikipedia.org/wiki/Bitwise_operations_in_C

In the context you asked about, it's being used to combine two flag values.