Specifies a Boolean value that indicates whether the atom must be created. If the atom name is not in the Host Portable Character Encoding, the result is implementation dependent. The atom will remain defined even after the client's connection closes. It will become undefined only when the last connection to the X server closes. The server failed to allocate the requested source or server memory.
Some numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.