utility_message.md

Utility Messages

Message Creation and Filtering

Utility Messages are represented by a

struct utility_message : universal_packet
{
    utility_message(status_t, uint16_t payload = 0u);

    // utility messages are groupless since UMP 1.1
    constexpr group_t group() const      = delete;
    constexpr void    set_group(group_t) = delete;
};

As Utility messages are groupless the group accessors are deleted.

Instead of using utility_message constructors one can create messages using factory functions:

constexpr utility_message make_utility_message(status_t, uint16_t data);

Filtering of Utility Messages can be done checking universal_packet::type() against packet_type::utility or use

bool universal_packet::is_utility_message();

Currently the only use case for Utility messages are Jitter Reduction Timestamps.

Message View

Once validated against packet_type::utility one can create a utility_message_view for a universal_packet:

struct utility_message_view
{
    utility_message_view(const universal_packet&);

    constexpr status_t status() const;
    constexpr uint16_t payload() const;
};