C FFI Reference

uint32_t coquic_ffi_abi_version(void);

Return the runtime C FFI ABI version.

Parameters:

• None.

Returns:

• The ABI version compiled into the loaded library.

Notes:

• Compare with COQUIC_FFI_ABI_VERSION before using a dynamically loaded library.

void coquic_transport_config_init(coquic_transport_config_t *config);

Initialize transport configuration defaults.

Parameters:

• config: output transport config. May be NULL.

Returns:

• Nothing.

Notes:

• NULL is a no-op.
• The initialized values mirror CoQUIC's C++ transport defaults.

void coquic_endpoint_config_init(coquic_endpoint_config_t *config);

Initialize endpoint configuration defaults.

Parameters:

• config: output endpoint config. May be NULL.

Returns:

• Nothing.

Notes:

• Sets config->size to sizeof(coquic_endpoint_config_t).
• Also initializes the embedded coquic_transport_config_t.
• NULL is a no-op.

void coquic_client_connection_config_init(coquic_client_connection_config_t *config);

Initialize client connection configuration defaults.

Parameters:

• config: output client connection config. May be NULL.

Returns:

• Nothing.

Notes:

• Sets config->size to sizeof(coquic_client_connection_config_t).
• Callers normally override connection IDs, versions, server name, resumption state, and 0-RTT config after initialization.

coquic_status_t coquic_endpoint_create(
    const coquic_endpoint_config_t *config,
    coquic_endpoint_t **out_endpoint);

Create a QUIC endpoint.

Parameters:

• config: initialized endpoint config.
• out_endpoint: receives the allocated endpoint handle.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT if config, out_endpoint, or config->size is invalid.
• COQUIC_STATUS_OUT_OF_MEMORY or COQUIC_STATUS_INTERNAL_ERROR on failure.

Notes:

• On failure, *out_endpoint is set to NULL when possible.
• Destroy successful outputs with coquic_endpoint_destroy().

void coquic_endpoint_destroy(coquic_endpoint_t *endpoint);

Destroy a QUIC endpoint.

Parameters:

• endpoint: endpoint handle to release. May be NULL.

Returns:

• Nothing.

Notes:

• Invalidates all connection handles owned by the endpoint.
• NULL is allowed.

coquic_status_t coquic_endpoint_open_connection(
    coquic_endpoint_t *endpoint,
    const coquic_open_connection_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Open a client connection through the Core endpoint API.

Parameters:

• endpoint: endpoint handle.
• input: initialized open-connection input.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT if required pointers or size fields are invalid.

Notes:

• input->size and input->connection.size must cover v1 fields.
• Process returned effects and destroy *out_result with coquic_result_destroy().

coquic_status_t coquic_endpoint_input_datagram(
    coquic_endpoint_t *endpoint,
    const coquic_inbound_datagram_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Feed one received UDP datagram into the endpoint.

Parameters:

• endpoint: endpoint handle.
• input: datagram bytes, optional route handle, address-validation identity, and ECN codepoint.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Input bytes are copied during the call.
• Preserve route-handle identity so send effects can be routed to the same path.

coquic_status_t coquic_endpoint_update_path_mtu(
    coquic_endpoint_t *endpoint,
    const coquic_path_mtu_update_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Notify the endpoint about a path MTU update.

Parameters:

• endpoint: endpoint handle.
• input: optional route handle and maximum UDP payload size.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Use the same route-handle namespace used for datagram input and output.

coquic_status_t coquic_endpoint_timer_expired(
    coquic_endpoint_t *endpoint,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Advance endpoint timers.

Parameters:

• endpoint: endpoint handle.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers.

Notes:

• Call when the deadline returned by coquic_result_next_wakeup() or coquic_endpoint_next_wakeup() fires.

coquic_status_t coquic_connection_send_stream(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_send_stream_data_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Send stream data on a connection.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: stream ID, bytes, and FIN flag.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Invalid connection or stream state is reported as a local error in the result.
• Input bytes are copied during the call.

coquic_status_t coquic_connection_send_datagram(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_send_datagram_data_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Send a QUIC DATAGRAM on a connection.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: datagram payload.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• DATAGRAM support and size failures are reported as local errors in the result.

coquic_status_t coquic_connection_reset_stream(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_reset_stream_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request RESET_STREAM.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: stream ID and application error code.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Stream-state failures are reported as local errors in the result.

coquic_status_t coquic_connection_stop_sending(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_stop_sending_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request STOP_SENDING.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: stream ID and application error code.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Stream-state failures are reported as local errors in the result.

coquic_status_t coquic_connection_close(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_close_connection_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request application close.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: application error code and reason phrase.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• The reason phrase is copied during the call.

coquic_status_t coquic_connection_request_key_update(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request a QUIC key update.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers.

Notes:

• Unsupported connection state is reported as a local error in the result.

coquic_status_t coquic_connection_request_migration(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_request_connection_migration_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request active connection migration.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: route handle, migration reason, and address-validation identity.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or input->size.

Notes:

• Address-validation identity bytes are copied during the call.

coquic_status_t coquic_connection_advance(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_connection_input_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Dispatch a tagged connection input.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• input: tagged coquic_connection_input_t.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or unsupported tags.

Notes:

• This is the preferred entry point for commands emitted by HTTP/3 updates.

coquic_status_t coquic_quic_connect(
    coquic_endpoint_t *endpoint,
    const coquic_open_connection_t *input,
    coquic_time_us_t now,
    coquic_connection_handle_t *out_connection,
    coquic_result_t **out_result);

Open a client connection through the QUIC facade.

Parameters:

• endpoint: endpoint handle.
• input: initialized open-connection input.
• now: monotonic timestamp in microseconds.
• out_connection: receives the created connection handle when present.
• out_result: receives the result object.

Returns:

• COQUIC_STATUS_OK on ABI-level success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers or size fields.

Notes:

• out_connection is set to 0 before validation.
• Effects still must be processed from out_result.

coquic_status_t coquic_quic_receive_datagram(
    coquic_endpoint_t *endpoint,
    const coquic_inbound_datagram_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for receiving a datagram.

Parameters:

• Same as coquic_endpoint_input_datagram().

Returns:

• Same as coquic_endpoint_input_datagram().

Notes:

• This function shares semantics with the Core endpoint datagram API.

coquic_status_t coquic_quic_update_path_mtu(
    coquic_endpoint_t *endpoint,
    const coquic_path_mtu_update_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for path MTU updates.

Parameters:

• Same as coquic_endpoint_update_path_mtu().

Returns:

• Same as coquic_endpoint_update_path_mtu().

Notes:

• This function exists for facade naming consistency.

coquic_status_t coquic_quic_timer_expired(
    coquic_endpoint_t *endpoint,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for timer expiry.

Parameters:

• Same as coquic_endpoint_timer_expired().

Returns:

• Same as coquic_endpoint_timer_expired().

Notes:

• This function exists for facade naming consistency.

coquic_status_t coquic_quic_connection_send_stream(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_send_stream_data_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for stream send.

Parameters:

• Same as coquic_connection_send_stream().

Returns:

• Same as coquic_connection_send_stream().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_send_datagram(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_send_datagram_data_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for DATAGRAM send.

Parameters:

• Same as coquic_connection_send_datagram().

Returns:

• Same as coquic_connection_send_datagram().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_reset_stream(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_reset_stream_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for RESET_STREAM.

Parameters:

• Same as coquic_connection_reset_stream().

Returns:

• Same as coquic_connection_reset_stream().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_stop_sending(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_stop_sending_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for STOP_SENDING.

Parameters:

• Same as coquic_connection_stop_sending().

Returns:

• Same as coquic_connection_stop_sending().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_close(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_close_connection_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for application close.

Parameters:

• Same as coquic_connection_close().

Returns:

• Same as coquic_connection_close().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_request_key_update(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for key update.

Parameters:

• Same as coquic_connection_request_key_update().

Returns:

• Same as coquic_connection_request_key_update().

Notes:

• Uses the same result and local-error behavior as the Core function.

coquic_status_t coquic_quic_connection_advance(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    const coquic_connection_input_t *input,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Facade alias for tagged connection input.

Parameters:

• Same as coquic_connection_advance().

Returns:

• Same as coquic_connection_advance().

Notes:

• Uses the same invalid-tag validation as the Core function.

coquic_status_t coquic_quic_stream_send(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_stream_id_t stream_id,
    coquic_bytes_t bytes,
    uint8_t fin,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Send stream data with facade-style parameters.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• stream_id: target stream ID.
• bytes: stream payload.
• fin: non-zero to mark FIN.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• Same status behavior as coquic_connection_send_stream().

Notes:

• Internally builds coquic_send_stream_data_t.

coquic_status_t coquic_quic_stream_finish(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_stream_id_t stream_id,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Send an empty FIN on a stream.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• stream_id: target stream ID.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• Same status behavior as coquic_quic_stream_send().

Notes:

• Equivalent to stream send with empty bytes and fin = 1.

coquic_status_t coquic_quic_stream_reset(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_stream_id_t stream_id,
    uint64_t application_error_code,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Reset a stream with facade-style parameters.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• stream_id: target stream ID.
• application_error_code: application error code.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• Same status behavior as coquic_connection_reset_stream().

Notes:

• Internally builds coquic_reset_stream_t.

coquic_status_t coquic_quic_stream_stop_sending(
    coquic_endpoint_t *endpoint,
    coquic_connection_handle_t connection,
    coquic_stream_id_t stream_id,
    uint64_t application_error_code,
    coquic_time_us_t now,
    coquic_result_t **out_result);

Request STOP_SENDING with facade-style parameters.

Parameters:

• endpoint: endpoint handle.
• connection: target connection handle.
• stream_id: target stream ID.
• application_error_code: application error code.
• now: monotonic timestamp in microseconds.
• out_result: receives the result object.

Returns:

• Same status behavior as coquic_connection_stop_sending().

Notes:

• Internally builds coquic_stop_sending_t.

size_t coquic_endpoint_connection_count(const coquic_endpoint_t *endpoint);

Return the number of endpoint-owned connections.

Parameters:

• endpoint: endpoint handle or NULL.

Returns:

• The connection count, or 0 for NULL.

Notes:

• This is a query only; it does not advance protocol state.

uint8_t coquic_endpoint_has_send_continuation_pending(
    const coquic_endpoint_t *endpoint);

Report whether endpoint send continuation work is pending.

Parameters:

• endpoint: endpoint handle or NULL.

Returns:

• Non-zero when send continuation work should continue.
• 0 for NULL.

Notes:

• If non-zero, call back into the endpoint without blocking.

coquic_optional_time_us_t coquic_endpoint_next_wakeup(
    const coquic_endpoint_t *endpoint);

Return the endpoint's current timer deadline.

Parameters:

• endpoint: endpoint handle or NULL.

Returns:

• Optional wakeup timestamp in microseconds.

Notes:

• Returns no value for NULL.

void coquic_result_destroy(coquic_result_t *result);

Destroy a result object.

Parameters:

• result: result handle or NULL.

Returns:

• Nothing.

Notes:

• Invalidates all borrowed byte views read from result effects.

size_t coquic_result_effect_count(const coquic_result_t *result);

Return the number of effects in a result.

Parameters:

• result: result handle or NULL.

Returns:

• Effect count, or 0 for NULL.

Notes:

• Use coquic_result_effect_at() for indices [0, count).

coquic_status_t coquic_result_effect_at(
    const coquic_result_t *result,
    size_t index,
    coquic_effect_t *out_effect);

Read one effect from a result.

Parameters:

• result: result handle.
• index: effect index.
• out_effect: output effect pointer.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT if the result, output pointer, or index is invalid.

Notes:

• Byte views inside out_effect are borrowed from result.

coquic_optional_time_us_t coquic_result_next_wakeup(
    const coquic_result_t *result);

Return the timer deadline from a result.

Parameters:

• result: result handle or NULL.

Returns:

• Optional wakeup timestamp in microseconds.

Notes:

• Prefer this immediately after processing a result.

uint8_t coquic_result_has_local_error(const coquic_result_t *result);

Report whether a result carries a local transport error.

Parameters:

• result: result handle or NULL.

Returns:

• Non-zero when a local error is present.
• 0 for NULL.

Notes:

• Read the error with coquic_result_local_error().

coquic_status_t coquic_result_local_error(
    const coquic_result_t *result,
    coquic_local_error_t *out_error);

Read a local transport error.

Parameters:

• result: result handle.
• out_error: output local error pointer.

Returns:

• COQUIC_STATUS_OK when an error was copied.
• COQUIC_STATUS_INVALID_ARGUMENT if no error is present or arguments are invalid.

Notes:

• Local errors are application signals; process any valid effects in the same result as usual.

uint8_t coquic_result_send_continuation_pending(
    const coquic_result_t *result);

Report send continuation state from a result.

Parameters:

• result: result handle or NULL.

Returns:

• Non-zero when send continuation work remains.
• 0 for NULL.

Notes:

• If non-zero, call back into the endpoint without blocking.

void coquic_http3_settings_init(coquic_http3_settings_t *settings);

Initialize HTTP/3 settings.

Parameters:

• settings: output settings pointer or NULL.

Returns:

• Nothing.

Notes:

• Sets settings->size to sizeof(coquic_http3_settings_t).
• NULL is a no-op.

void coquic_http3_client_config_init(coquic_http3_client_config_t *config);

Initialize HTTP/3 client config.

Parameters:

• config: output client config pointer or NULL.

Returns:

• Nothing.

Notes:

• Initializes embedded local HTTP/3 settings.

void coquic_http3_server_config_init(coquic_http3_server_config_t *config);

Initialize HTTP/3 server config.

Parameters:

• config: output server config pointer or NULL.

Returns:

• Nothing.

Notes:

• Initializes embedded local HTTP/3 settings.

void coquic_http3_client_endpoint_config_init(coquic_endpoint_config_t *config);

Initialize a QUIC endpoint config for HTTP/3 client use.

Parameters:

• config: output endpoint config pointer or NULL.

Returns:

• Nothing.

Notes:

• Sets role to COQUIC_ROLE_CLIENT and ALPN to h3.
• Calls coquic_endpoint_config_init() first.

void coquic_http3_server_endpoint_config_init(coquic_endpoint_config_t *config);

Initialize a QUIC endpoint config for HTTP/3 server use.

Parameters:

• config: output endpoint config pointer or NULL.

Returns:

• Nothing.

Notes:

• Sets role to COQUIC_ROLE_SERVER and ALPN to h3.
• Server TLS identity remains caller-configured.

coquic_status_t coquic_http3_client_create(
    const coquic_http3_client_config_t *config,
    coquic_http3_client_t **out_client);

Create HTTP/3 client state.

Parameters:

• config: initialized client config.
• out_client: receives the client handle.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or size fields.

Notes:

• The client object is per QUIC connection.
• Destroy with coquic_http3_client_destroy().

void coquic_http3_client_destroy(coquic_http3_client_t *client);

Destroy HTTP/3 client state.

Parameters:

• client: client handle or NULL.

Returns:

• Nothing.

Notes:

• Does not destroy the QUIC endpoint.

coquic_status_t coquic_http3_client_submit_request(
    coquic_http3_client_t *client,
    const coquic_http3_request_t *request,
    coquic_stream_id_t *out_stream_id,
    coquic_http3_error_t *out_error);

Queue an HTTP/3 request.

Parameters:

• client: client handle.
• request: initialized request object.
• out_stream_id: receives the request stream ID.
• out_error: optional protocol error output.

Returns:

• COQUIC_STATUS_OK when the C call completed.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers or size fields.

Notes:

• An HTTP/3 rejection can be reported through out_error while returning COQUIC_STATUS_OK.
• out_error->detail_buffer is caller-owned and preserved across the call.

coquic_status_t coquic_http3_client_on_quic_result(
    coquic_http3_client_t *client,
    const coquic_result_t *result,
    coquic_time_us_t now,
    coquic_http3_client_update_t **out_update);

Feed a QUIC result into HTTP/3 client state.

Parameters:

• client: client handle.
• result: borrowed QUIC result.
• now: monotonic timestamp in microseconds.
• out_update: receives the client update.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers.

Notes:

• The caller still owns result.
• Destroy the update with coquic_http3_client_update_destroy().

coquic_status_t coquic_http3_client_poll(
    coquic_http3_client_t *client,
    coquic_time_us_t now,
    coquic_http3_client_update_t **out_update);

Poll pending HTTP/3 client work.

Parameters:

• client: client handle.
• now: monotonic timestamp in microseconds.
• out_update: receives the client update.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers.

Notes:

• Poll again while coquic_http3_client_update_has_pending_work() is non-zero.

uint8_t coquic_http3_client_has_failed(const coquic_http3_client_t *client);

Report terminal client failure.

Parameters:

• client: client handle or NULL.

Returns:

• Non-zero after terminal HTTP/3 client failure.
• 0 for NULL.

Notes:

• Terminal failure is HTTP/3-layer state, not endpoint ownership state.

void coquic_http3_client_update_destroy(
    coquic_http3_client_update_t *update);

Destroy a client update.

Parameters:

• update: update handle or NULL.

Returns:

• Nothing.

Notes:

• Invalidates all response views and emitted connection-input byte pointers borrowed from the update.

size_t coquic_http3_client_update_connection_input_count(
    const coquic_http3_client_update_t *update);

Return the number of emitted QUIC connection inputs.

Parameters:

• update: client update or NULL.

Returns:

• Input count, or 0 for NULL.

Notes:

• Feed each input to the matching QUIC connection.

coquic_status_t coquic_http3_client_update_connection_input_at(
    const coquic_http3_client_update_t *update,
    size_t index,
    coquic_connection_input_t *out_input);

Read one emitted QUIC connection input.

Parameters:

• update: client update.
• index: input index.
• out_input: output connection input.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Byte pointers inside out_input are borrowed from update.

size_t coquic_http3_client_update_response_count(
    const coquic_http3_client_update_t *update);

Return the number of completed response events.

Parameters:

• update: client update or NULL.

Returns:

• Response event count, or 0 for NULL.

Notes:

• Read events with coquic_http3_client_update_response_at().

coquic_status_t coquic_http3_client_update_response_at(
    const coquic_http3_client_update_t *update,
    size_t index,
    coquic_http3_client_response_event_t *out_event);

Read one completed response event.

Parameters:

• update: client update.
• index: response event index.
• out_event: output event pointer.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Request and response views inside out_event are borrowed from update.

size_t coquic_http3_client_update_request_error_count(
    const coquic_http3_client_update_t *update);

Return the number of request error events.

Parameters:

• update: client update or NULL.

Returns:

• Request error count, or 0 for NULL.

Notes:

• Read events with coquic_http3_client_update_request_error_at().

coquic_status_t coquic_http3_client_update_request_error_at(
    const coquic_http3_client_update_t *update,
    size_t index,
    coquic_http3_client_request_error_event_t *out_event);

Read one request error event.

Parameters:

• update: client update.
• index: request error event index.
• out_event: output event pointer.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Request views inside out_event are borrowed from update.

uint8_t coquic_http3_client_update_has_pending_work(
    const coquic_http3_client_update_t *update);

Report whether the client has immediate pending work.

Parameters:

• update: client update or NULL.

Returns:

• Non-zero when the caller should poll again immediately.
• 0 for NULL.

Notes:

• Do not wait for network input before polling again when this is non-zero.

uint8_t coquic_http3_client_update_terminal_failure(
    const coquic_http3_client_update_t *update);

Report terminal client failure in an update.

Parameters:

• update: client update or NULL.

Returns:

• Non-zero when this update reports terminal HTTP/3 client failure.
• 0 for NULL.

Notes:

• This mirrors update state; coquic_http3_client_has_failed() queries the client object.

uint8_t coquic_http3_client_update_handled_local_error(
    const coquic_http3_client_update_t *update);

Report whether a QUIC local error was consumed by HTTP/3 client state.

Parameters:

• update: client update or NULL.

Returns:

• Non-zero when a QUIC local error was handled.
• 0 for NULL.

Notes:

• This is useful for bindings that separately log QUIC local errors.

coquic_status_t coquic_http3_server_create(
    const coquic_http3_server_config_t *config,
    coquic_http3_server_t **out_server);

Create HTTP/3 server state.

Parameters:

• config: initialized server config.
• out_server: receives the server handle.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid pointers or size fields.

Notes:

• The server object is per QUIC connection.
• Destroy with coquic_http3_server_destroy().

void coquic_http3_server_destroy(coquic_http3_server_t *server);

Destroy HTTP/3 server state.

Parameters:

• server: server handle or NULL.

Returns:

• Nothing.

Notes:

• Does not destroy the QUIC endpoint.

coquic_status_t coquic_http3_server_on_quic_result(
    coquic_http3_server_t *server,
    const coquic_result_t *result,
    coquic_time_us_t now,
    coquic_http3_server_update_t **out_update);

Feed a QUIC result into HTTP/3 server state.

Parameters:

• server: server handle.
• result: borrowed QUIC result.
• now: monotonic timestamp in microseconds.
• out_update: receives the server update.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers.

Notes:

• The caller still owns result.
• Destroy the update with coquic_http3_server_update_destroy().

coquic_status_t coquic_http3_server_poll(
    coquic_http3_server_t *server,
    coquic_time_us_t now,
    coquic_http3_server_update_t **out_update);

Poll pending HTTP/3 server work.

Parameters:

• server: server handle.
• now: monotonic timestamp in microseconds.
• out_update: receives the server update.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid required pointers.

Notes:

• Poll again while coquic_http3_server_update_has_pending_work() is non-zero.

uint8_t coquic_http3_server_has_failed(const coquic_http3_server_t *server);

Report terminal server failure.

Parameters:

• server: server handle or NULL.

Returns:

• Non-zero after terminal HTTP/3 server failure.
• 0 for NULL.

Notes:

• Terminal failure is HTTP/3-layer state, not endpoint ownership state.

void coquic_http3_server_update_destroy(
    coquic_http3_server_update_t *update);

Destroy a server update.

Parameters:

• update: update handle or NULL.

Returns:

• Nothing.

Notes:

• Invalidates all request views and emitted connection-input byte pointers borrowed from the update.

size_t coquic_http3_server_update_connection_input_count(
    const coquic_http3_server_update_t *update);

Return the number of emitted QUIC connection inputs.

Parameters:

• update: server update or NULL.

Returns:

• Input count, or 0 for NULL.

Notes:

• Feed each input to the matching QUIC connection.

coquic_status_t coquic_http3_server_update_connection_input_at(
    const coquic_http3_server_update_t *update,
    size_t index,
    coquic_connection_input_t *out_input);

Read one emitted QUIC connection input.

Parameters:

• update: server update.
• index: input index.
• out_input: output connection input.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Byte pointers inside out_input are borrowed from update.

size_t coquic_http3_server_update_request_cancelled_count(
    const coquic_http3_server_update_t *update);

Return the number of request cancellation events.

Parameters:

• update: server update or NULL.

Returns:

• Cancellation event count, or 0 for NULL.

Notes:

• Read events with coquic_http3_server_update_request_cancelled_at().

coquic_status_t coquic_http3_server_update_request_cancelled_at(
    const coquic_http3_server_update_t *update,
    size_t index,
    coquic_http3_server_request_cancelled_event_t *out_event);

Read one server request cancellation event.

Parameters:

• update: server update.
• index: cancellation event index.
• out_event: output event pointer.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Views inside out_event are borrowed from update.

uint8_t coquic_http3_server_update_has_pending_work(
    const coquic_http3_server_update_t *update);

Report whether the server has immediate pending work.

Parameters:

• update: server update or NULL.

Returns:

• Non-zero when the caller should poll again immediately.
• 0 for NULL.

Notes:

• Do not wait for network input before polling again when this is non-zero.

uint8_t coquic_http3_server_update_terminal_failure(
    const coquic_http3_server_update_t *update);

Report terminal server failure in an update.

Parameters:

• update: server update or NULL.

Returns:

• Non-zero when this update reports terminal HTTP/3 server failure.
• 0 for NULL.

Notes:

• This mirrors update state; coquic_http3_server_has_failed() queries the server object.

uint8_t coquic_http3_server_update_handled_local_error(
    const coquic_http3_server_update_t *update);

Report whether a QUIC local error was consumed by HTTP/3 server state.

Parameters:

• update: server update or NULL.

Returns:

• Non-zero when a QUIC local error was handled.
• 0 for NULL.

Notes:

• This is useful for bindings that separately log QUIC local errors.

coquic_status_t coquic_http3_request_view_header_at(
    const coquic_http3_request_view_t *request,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a request header view.

Parameters:

• request: borrowed request view.
• index: header index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_request_view_trailer_at(
    const coquic_http3_request_view_t *request,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a request trailer view.

Parameters:

• request: borrowed request view.
• index: trailer index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_request_head_view_header_at(
    const coquic_http3_request_head_view_t *head,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a request-head header view.

Parameters:

• head: borrowed request head view.
• index: header index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_response_view_interim_head_at(
    const coquic_http3_response_view_t *response,
    size_t index,
    coquic_http3_response_head_view_t *out_head);

Read an interim response head.

Parameters:

• response: borrowed response view.
• index: interim head index.
• out_head: receives the response head view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Header arrays inside out_head are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_response_view_header_at(
    const coquic_http3_response_view_t *response,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a final response header view.

Parameters:

• response: borrowed response view.
• index: header index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_response_view_trailer_at(
    const coquic_http3_response_view_t *response,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a response trailer view.

Parameters:

• response: borrowed response view.
• index: trailer index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_response_head_view_header_at(
    const coquic_http3_response_head_view_t *head,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a response-head header view.

Parameters:

• head: borrowed response head view.
• index: header index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.

coquic_status_t coquic_http3_server_request_cancelled_view_trailer_at(
    const coquic_http3_server_request_cancelled_event_t *event,
    size_t index,
    coquic_http3_field_view_t *out_field);

Read a trailer from a server request cancellation event.

Parameters:

• event: borrowed cancellation event.
• index: trailer index.
• out_field: receives the field view.

Returns:

• COQUIC_STATUS_OK on success.
• COQUIC_STATUS_INVALID_ARGUMENT for invalid arguments or index.

Notes:

• Returned name and value views are borrowed from the owning HTTP/3 update.