* - @ref Configuration (baud rate, parity, etc.)
* - @ref Signals (modem control lines, breaks, etc.)
* - @ref Data
+ * - @ref Waiting
* - @ref Errors
*
* libserialport is an open source project released under the LGPL3+ license.
*
* Calls that succeed return @ref SP_OK, which is equal to zero. Some functions
* declared @ref sp_return can also return a positive value for a successful
- * numeric result, e.g. sp_read() and sp_write().
+ * numeric result, e.g. sp_blocking_read() or sp_blocking_write().
*/
#ifndef LIBSERIALPORT_LIBSERIALPORT_H
SP_MODE_READ = 1,
/** Open port for write access. */
SP_MODE_WRITE = 2,
- /** Open port in non-blocking mode. */
- SP_MODE_NONBLOCK = 4,
+};
+
+/** Port events. */
+enum sp_event {
+ /* Data received and ready to read. */
+ SP_EVENT_RX_READY = 1,
+ /* Ready to transmit new data. */
+ SP_EVENT_TX_READY = 2,
+ /* Error occured. */
+ SP_EVENT_ERROR = 4,
};
/** Buffer selection. */
SP_PARITY_ODD = 1,
/** Even parity. */
SP_PARITY_EVEN = 2,
+ /** Mark parity. */
+ SP_PARITY_MARK = 3,
+ /** Space parity. */
+ SP_PARITY_SPACE = 4,
};
/** RTS pin behaviour. */
SP_SIG_RI = 8,
};
-/** A serial port. */
+/**
+ * @struct sp_port
+ * An opaque structure representing a serial port.
+ */
struct sp_port;
-/** Configuration for a serial port. */
+/**
+ * @struct sp_port_config
+ * An opaque structure representing the configuration for a serial port.
+ */
struct sp_port_config;
+/**
+ * @struct sp_event_set
+ * A set of handles to wait on for events.
+ */
+struct sp_event_set {
+ /** Array of OS-specific handles. */
+ void *handles;
+ /** Array of bitmasks indicating which events apply for each handle. */
+ enum sp_event *masks;
+ /** Number of handles. */
+ unsigned int count;
+};
+
/**
@defgroup Enumeration Port enumeration
@{
*/
/**
- * Read bytes from the specified serial port.
+ * Read bytes from the specified serial port, blocking until complete.
+ *
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort blocking reads when these are called, then you
+ * should not use this function. It repeats system calls that return
+ * with EINTR. To be able to abort a read from a signal handler, you
+ * should implement your own blocking read using sp_nonblocking_read()
+ * together with a blocking method that makes sense for your program.
+ * E.g. you can obtain the file descriptor for an open port using
+ * sp_get_port_handle() and use this to call select() or pselect(),
+ * with appropriate arrangements to return if a signal is received.
*
- * 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 Requested number of bytes to read.
+ * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
+ *
+ * @return The number of bytes read on success, or a negative error code. If
+ * the number of bytes returned is less than that requested, the
+ * timeout was reached before the requested number of bytes was
+ * available. If timeout is zero, the function will always return
+ * either the requested number of bytes or a negative error code.
+ */
+enum sp_return sp_blocking_read(struct sp_port *port, void *buf, size_t count, unsigned int timeout);
+
+/**
+ * Read bytes from the specified serial port, without blocking.
*
* @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.
+ * @return The number of bytes read on success, or a negative error code. The
+ * number of bytes returned may be any number from zero to the maximum
+ * that was requested.
+ */
+enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf, size_t count);
+
+/**
+ * Write bytes to the specified serial port, blocking until complete.
+ *
+ * Note that this function only ensures that the accepted bytes have been
+ * written to the OS; they may be held in driver or hardware buffers and not
+ * yet physically transmitted. To check whether all written bytes have actually
+ * been transmitted, use the sp_output_waiting() function. To wait until all
+ * written bytes have actually been transmitted, use the sp_drain() function.
+ *
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort blocking writes when these are called, then you
+ * should not use this function. It repeats system calls that return
+ * with EINTR. To be able to abort a write from a signal handler, you
+ * should implement your own blocking write using sp_nonblocking_write()
+ * together with a blocking method that makes sense for your program.
+ * E.g. you can obtain the file descriptor for an open port using
+ * sp_get_port_handle() and use this to call select() or pselect(),
+ * with appropriate arrangements to return if a signal is received.
+ *
+ * @param port Pointer to port structure.
+ * @param buf Buffer containing the bytes to write.
+ * @param count Requested number of bytes to write.
+ * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
+ *
+ * @return The number of bytes written on success, or a negative error code.
+ * If the number of bytes returned is less than that requested, the
+ * timeout was reached before the requested number of bytes was
+ * written. If timeout is zero, the function will always return
+ * either the requested number of bytes or a negative error code. In
+ * the event of an error there is no way to determine how many bytes
+ * were sent before the error occured.
*/
-enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
+enum sp_return sp_blocking_write(struct sp_port *port, const void *buf, size_t count, unsigned int timeout);
/**
- * Write bytes to the specified serial port.
+ * Write bytes to the specified serial port, without blocking.
*
- * 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.
+ * Note that this function only ensures that the accepted bytes have been
+ * written to the OS; they may be held in driver or hardware buffers and not
+ * yet physically transmitted. To check whether all written bytes have actually
+ * been transmitted, use the sp_output_waiting() function. To wait until all
+ * written bytes have actually been transmitted, use the sp_drain() function.
*
* @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.
+ * The number of bytes returned may be any number from zero to the
+ * maximum that was requested.
*/
-enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
+enum sp_return sp_nonblocking_write(struct sp_port *port, const void *buf, size_t count);
+
+/**
+ * Gets the number of bytes waiting in the input buffer.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return Number of bytes waiting on success, a negative error code otherwise.
+ */
+enum sp_return sp_input_waiting(struct sp_port *port);
+
+/**
+ * Gets the number of bytes waiting in the output buffer.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return Number of bytes waiting on success, a negative error code otherwise.
+ */
+enum sp_return sp_output_waiting(struct sp_port *port);
/**
* Flush serial port buffers. Data in the selected buffer(s) is discarded.
/**
* Wait for buffered data to be transmitted.
*
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort draining the output buffer when when these are
+ * called, then you should not use this function. It repeats system
+ * calls that return with EINTR. To be able to abort a drain from a
+ * signal handler, you would need to implement your own blocking
+ * drain by polling the result of sp_output_waiting().
+ *
* @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 Waiting Waiting for events
+ * @{
+ */
+
+/**
+ * Allocate storage for a set of events.
+ *
+ * The user should allocate a variable of type struct sp_event_set *,
+ * then pass a pointer to this variable to receive the result.
+ *
+ * The result should be freed after use by calling sp_free_event_set().
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_new_event_set(struct sp_event_set **result_ptr);
+
+/**
+ * Add events to a struct sp_event_set for a given port.
+ *
+ * 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 results may
+ * no longer be valid.
+ *
+ * @param event_set Event set to update.
+ * @param port Pointer to port structure.
+ * @param mask Bitmask of events to be waited for.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_add_port_events(struct sp_event_set *event_set,
+ const struct sp_port *port, enum sp_event mask);
+
+/**
+ * Wait for any of a set of events to occur.
+ *
+ * @param event_set Event set to wait on.
+ * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
+ *
+ * @return SP_OK upon success, a negative error code otherwise.
+ */
+enum sp_return sp_wait(struct sp_event_set *event_set, unsigned int timeout);
+
+/**
+ * Free a structure allocated by sp_new_event_set().
+ */
+void sp_free_event_set(struct sp_event_set *event_set);
+
/**
* @}
* @defgroup Signals Port signalling operations
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