The documentation of this enum
renders like this:
The correct syntax would probably be
enum Category
{
genericParameter = (0 << 16) | 0, ///< If your parameter is not a meter then you should use this category
inputGain = (1 << 16) | 0, ///< Currently not used
outputGain = (1 << 16) | 1, ///< Currently not used
inputMeter = (2 << 16) | 0, ///< Read-only input meter value. Most hosts will display these type of parameters as a meter in the generic view of your plug-in. Pro-Tools will also show the meter in the mixer view.
outputMeter = (2 << 16) | 1, ///< Read-only output meter value. Most hosts will display these type of parameters as a meter in the generic view of your plug-in. Pro-Tools will also show the meter in the mixer view.
compressorLimiterGainReductionMeter = (2 << 16) | 2, ///< Read-only compressor GR meter value. Most hosts will display these type of parameters as a meter in the generic view of your plug-in. Pro-Tools will also show the meter in the mixer view.
expanderGateGainReductionMeter = (2 << 16) | 3, ///< Read-only expander/gate GR meter value. Most hosts will display these type of parameters as a meter in the generic view of your plug-in. Pro-Tools will also show the meter in the mixer view.
analysisMeter = (2 << 16) | 4, ///< Whatever an analysis meter is?? :D
otherMeter = (2 << 16) | 5
};