+/**
+ * @}
+ * @defgroup Ports Opening, closing and querying ports
+ * @{
+ */
+
+/**
+ * Open the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param flags Flags to use when opening the serial port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
+
+/**
+ * Close the specified serial port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_close(struct sp_port *port);
+
+/**
+ * Get the name of a port.
+ *
+ * The name returned is whatever is normally used to refer to a port on the
+ * current operating system; e.g. for Windows it will usually be a "COMn"
+ * device name, and for Unix it will be a device path beginning with "/dev/".
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return The port name, or NULL if an invalid port is passed. The name
+ * string is part of the port structure and may not be used after the
+ * port structure has been freed.
+ */
+char *sp_get_port_name(const struct sp_port *port);
+
+/**
+ * Get the operating system handle for a port.
+ *
+ * The type of the handle depends on the operating system. On Unix based
+ * systems, the handle is a file descriptor of type "int". On Windows, the
+ * handle is of type "HANDLE". The user should allocate a variable of the
+ * appropriate type and pass a pointer to this to receive the result.
+ *
+ * To obtain a valid handle, the port must first be opened by calling
+ * sp_open() using the same port structure.
+ *
+ * After the port is closed or the port structure freed, the handle may
+ * no longer be valid.
+ *
+ * @warning This feature is provided so that programs may make use of
+ * OS-specific functionality where desired. Doing so obviously
+ * comes at a cost in portability. It also cannot be guaranteed
+ * that direct usage of the OS handle will not conflict with the
+ * library's own usage of the port. Be careful.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_port_handle(const struct sp_port *port, void *result_ptr);
+
+/**
+ * @}
+ * @defgroup Configuration Setting port parameters
+ * @{
+ */
+
+/**
+ * Allocate a port configuration structure.
+ *
+ * The user should allocate a variable of type "struct sp_config *" and pass a
+ * pointer to this to receive the result. The variable will be updated to
+ * point to the new configuration structure. The structure is opaque and must
+ * be accessed via the functions provided.
+ *
+ * All parameters in the structure will be initialised to special values which
+ * are ignored by sp_set_config().
+ *
+ * The structure should be freed after use by calling sp_free_config().
+ *
+ * @param config_ptr Pointer to variable to receive result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_new_config(struct sp_port_config **config_ptr);
+
+/**
+ * Free a port configuration structure.
+ *
+ * @param config Pointer to configuration structure.
+ */
+void sp_free_config(struct sp_port_config *config);
+
+/**
+ * Get the current configuration of the specified serial port.
+ *
+ * The user should allocate a configuration structure using sp_new_config()
+ * and pass this as the config parameter. The configuration structure will
+ * be updated with the port configuration.
+ *
+ * Any parameters that are configured with settings not recognised or
+ * supported by libserialport, will be set to special values that are
+ * ignored by sp_set_config().
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
+
+/**
+ * Set the configuration for the specified serial port.
+ *
+ * For each parameter in the configuration, there is a special value (usually
+ * -1, but see the documentation for each field). These values will be ignored
+ * and the corresponding setting left unchanged on the port.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
+
+/**
+ * Set the baud rate for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param baudrate Baud rate in bits per second.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate);
+
+/**
+ * Get the baud rate from a port configuration.
+ *
+ * The user should allocate a variable of type int and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param baudrate_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_baudrate(const struct sp_port_config *config, int *baudrate_ptr);
+
+/**
+ * Set the baud rate in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param baudrate Baud rate in bits per second, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_baudrate(struct sp_port_config *config, int baudrate);
+
+/**
+ * Set the data bits for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param bits Number of data bits.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_bits(struct sp_port *port, int bits);
+
+/**
+ * Get the data bits from a port configuration.
+ *
+ * The user should allocate a variable of type int and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param bits_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_bits(const struct sp_port_config *config, int *bits_ptr);
+
+/**
+ * Set the data bits in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param bits Number of data bits, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_bits(struct sp_port_config *config, int bits);
+
+/**
+ * Set the parity setting for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param parity Parity setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity);
+
+/**
+ * Get the parity setting from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_parity and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param parity_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_parity(const struct sp_port_config *config, enum sp_parity *parity_ptr);
+
+/**
+ * Set the parity setting in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param parity Parity setting, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_parity(struct sp_port_config *config, enum sp_parity parity);
+
+/**
+ * Set the stop bits for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param stopbits Number of stop bits.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits);
+
+/**
+ * Get the stop bits from a port configuration.
+ *
+ * The user should allocate a variable of type int and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param stopbits_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_stopbits(const struct sp_port_config *config, int *stopbits_ptr);
+
+/**
+ * Set the stop bits in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param stopbits Number of stop bits, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_stopbits(struct sp_port_config *config, int stopbits);
+
+/**
+ * Set the RTS pin behaviour for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param rts RTS pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts);
+
+/**
+ * Get the RTS pin behaviour from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_rts and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param rts_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_rts(const struct sp_port_config *config, enum sp_rts *rts_ptr);
+
+/**
+ * Set the RTS pin behaviour in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param rts RTS pin mode, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_rts(struct sp_port_config *config, enum sp_rts rts);
+
+/**
+ * Set the CTS pin behaviour for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param cts CTS pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts);
+
+/**
+ * Get the CTS pin behaviour from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_cts and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param cts_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_cts(const struct sp_port_config *config, enum sp_cts *cts_ptr);
+
+/**
+ * Set the CTS pin behaviour in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param cts CTS pin mode, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_cts(struct sp_port_config *config, enum sp_cts cts);
+
+/**
+ * Set the DTR pin behaviour for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param dtr DTR pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr);
+
+/**
+ * Get the DTR pin behaviour from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_dtr and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param dtr_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_dtr(const struct sp_port_config *config, enum sp_dtr *dtr_ptr);
+
+/**
+ * Set the DTR pin behaviour in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param dtr DTR pin mode, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_dtr(struct sp_port_config *config, enum sp_dtr dtr);
+
+/**
+ * Set the DSR pin behaviour for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param dsr DSR pin mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr);
+
+/**
+ * Get the DSR pin behaviour from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_dsr and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param dsr_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_dsr(const struct sp_port_config *config, enum sp_dsr *dsr_ptr);
+
+/**
+ * Set the DSR pin behaviour in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param dsr DSR pin mode, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_dsr(struct sp_port_config *config, enum sp_dsr dsr);
+
+/**
+ * Set the XON/XOFF configuration for the specified serial port.
+ *
+ * @param port Pointer to port structure.
+ * @param xon_xoff XON/XOFF mode.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
+
+/**
+ * Get the XON/XOFF configuration from a port configuration.
+ *
+ * The user should allocate a variable of type enum sp_xonxoff and pass a pointer to this
+ * to receive the result.
+ *
+ * @param config Pointer to configuration structure.
+ * @param xon_xoff_ptr Pointer to variable to store result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_config_xon_xoff(const struct sp_port_config *config, enum sp_xonxoff *xon_xoff_ptr);
+
+/**
+ * Set the XON/XOFF configuration in a port configuration.
+ *
+ * @param config Pointer to configuration structure.
+ * @param xon_xoff XON/XOFF mode, or -1 to retain current setting.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_xon_xoff(struct sp_port_config *config, enum sp_xonxoff xon_xoff);
+
+/**
+ * Set the flow control type in a port configuration.
+ *
+ * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
+ * XON/XOFF settings as necessary for the specified flow control
+ * type. For more fine-grained control of these settings, use their
+ * individual configuration functions.
+ *
+ * @param config Pointer to configuration structure.
+ * @param flowcontrol Flow control setting to use.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_config_flowcontrol(struct sp_port_config *config, enum sp_flowcontrol flowcontrol);
+
+/**
+ * Set the flow control type for the specified serial port.
+ *
+ * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
+ * XON/XOFF settings as necessary for the specified flow control
+ * type. For more fine-grained control of these settings, use their
+ * individual configuration functions.
+ *
+ * @param port Pointer to port structure.
+ * @param flowcontrol Flow control setting to use.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
+
+/**
+ * @}
+ * @defgroup Data Reading, writing, and flushing data
+ * @{
+*/
+
+/**
+ * Read bytes from the specified serial port.
+ *
+ * Note that this function may return after reading less than the specified
+ * number of bytes; it is the user's responsibility to iterate as necessary
+ * in this case.
+ *
+ * @param port Pointer to port structure.
+ * @param buf Buffer in which to store the bytes read.
+ * @param count Maximum number of bytes to read.
+ *
+ * @return The number of bytes read on success, or a negative error code.
+ */
+enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
+
+/**
+ * Write bytes to the specified serial port.
+ *
+ * Note that this function may return after writing less than the specified
+ * number of bytes; it is the user's responsibility to iterate as necessary
+ * in this case.
+ *
+ * @param port Pointer to port structure.
+ * @param buf Buffer containing the bytes to write.
+ * @param count Maximum number of bytes to write.
+ *
+ * @return The number of bytes written on success, or a negative error code.
+ */
+enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
+
+/**
+ * Flush serial port buffers. Data in the selected buffer(s) is discarded.
+ *
+ * @param port Pointer to port structure.
+ * @param buffers Which buffer(s) to flush.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
+
+/**
+ * Wait for buffered data to be transmitted.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_drain(struct sp_port *port);
+
+/**
+ * @}
+ * @defgroup Signals Port signalling operations
+ * @{
+ */
+
+/**
+ * Gets the status of the control signals for the specified port.
+ *
+ * The user should allocate a variable of type "enum sp_signal" and pass a
+ * pointer to this variable to receive the result. The result is a bitmask
+ * in which individual signals can be checked by bitwise OR with values of
+ * the sp_signal enum.
+ *
+ * @param port Pointer to port structure.
+ * @param signals Pointer to variable to receive result.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals);
+
+/**
+ * Put the port transmit line into the break state.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_start_break(struct sp_port *port);
+
+/**
+ * Take the port transmit line out of the break state.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_end_break(struct sp_port *port);
+
+/**
+ * @}
+ * @defgroup Errors Obtaining error information
+ * @{
+*/
+
+/**
+ * Get the error code for a failed operation.
+ *
+ * In order to obtain the correct result, this function should be called
+ * straight after the failure, before executing any other system operations.
+ *
+ * @return The system's numeric code for the error that caused the last
+ * operation to fail.
+ */