2 * This file is part of the libserialport project.
4 * Copyright (C) 2013 Martin Ling <martin-libserialport@earth.li>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as
8 * published by the Free Software Foundation, either version 3 of the
9 * License, or (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * @mainpage libserialport API
26 * libserialport is a minimal library written in C that is intended to take
27 * care of the OS-specific details when writing software that uses serial ports.
29 * By writing your serial code to use libserialport, you enable it to work
30 * transparently on any platform supported by the library.
32 * The operations that are supported are:
34 * - @ref Enumeration (obtaining a list of serial ports on the system)
36 * - @ref Configuration (baud rate, parity, etc.)
37 * - @ref Signals (modem control lines, breaks, etc.)
42 * libserialport is an open source project released under the LGPL3+ license.
47 * The API is simple, and designed to be a minimal wrapper around the serial
48 * port support in each OS.
50 * Most functions take a pointer to a struct sp_port, which represents a serial
51 * port. These structures are always allocated and freed by the library, using
52 * the functions in the @ref Enumeration "Enumeration" section.
54 * Most functions have return type @ref sp_return and can return only four
55 * possible error values:
57 * - @ref SP_ERR_ARG means that a function was called with invalid
58 * arguments. This implies a bug in the caller. The arguments passed would
59 * be invalid regardless of the underlying OS or serial device involved.
61 * - @ref SP_ERR_FAIL means that the OS reported a failure. The error code or
62 * message provided by the OS can be obtained by calling sp_last_error_code()
63 * or sp_last_error_message().
65 * - @ref SP_ERR_SUPP indicates that there is no support for the requested
66 * operation in the current OS, driver or device. No error message is
67 * available from the OS in this case. There is either no way to request
68 * the operation in the first place, or libserialport does not know how to
69 * do so in the current version.
71 * - @ref SP_ERR_MEM indicates that a memory allocation failed.
73 * All of these error values are negative.
75 * Calls that succeed return @ref SP_OK, which is equal to zero. Some functions
76 * declared @ref sp_return can also return a positive value for a successful
77 * numeric result, e.g. sp_blocking_read() or sp_blocking_write().
80 #ifndef LIBSERIALPORT_LIBSERIALPORT_H
81 #define LIBSERIALPORT_LIBSERIALPORT_H
94 /** Operation completed successfully. */
96 /** Invalid arguments were passed to the function. */
98 /** A system error occured while executing the operation. */
100 /** A memory allocation failed while executing the operation. */
102 /** The requested operation is not supported by this system or device. */
106 /** Port access modes. */
108 /** Open port for read access. */
110 /** Open port for write access. */
116 /* Data received and ready to read. */
117 SP_EVENT_RX_READY = 1,
118 /* Ready to transmit new data. */
119 SP_EVENT_TX_READY = 2,
124 /** Buffer selection. */
128 /** Output buffer. */
134 /** Parity settings. */
136 /** Special value to indicate setting should be left alone. */
137 SP_PARITY_INVALID = -1,
150 /** RTS pin behaviour. */
152 /** Special value to indicate setting should be left alone. */
158 /** RTS used for flow control. */
159 SP_RTS_FLOW_CONTROL = 2,
162 /** CTS pin behaviour. */
164 /** Special value to indicate setting should be left alone. */
168 /** CTS used for flow control. */
169 SP_CTS_FLOW_CONTROL = 1,
172 /** DTR pin behaviour. */
174 /** Special value to indicate setting should be left alone. */
180 /** DTR used for flow control. */
181 SP_DTR_FLOW_CONTROL = 2,
184 /** DSR pin behaviour. */
186 /** Special value to indicate setting should be left alone. */
190 /** DSR used for flow control. */
191 SP_DSR_FLOW_CONTROL = 1,
194 /** XON/XOFF flow control behaviour. */
196 /** Special value to indicate setting should be left alone. */
197 SP_XONXOFF_INVALID = -1,
198 /** XON/XOFF disabled. */
199 SP_XONXOFF_DISABLED = 0,
200 /** XON/XOFF enabled for input only. */
202 /** XON/XOFF enabled for output only. */
204 /** XON/XOFF enabled for input and output. */
205 SP_XONXOFF_INOUT = 3,
208 /** Standard flow control combinations. */
209 enum sp_flowcontrol {
210 /** No flow control. */
211 SP_FLOWCONTROL_NONE = 0,
212 /** Software flow control using XON/XOFF characters. */
213 SP_FLOWCONTROL_XONXOFF = 1,
214 /** Hardware flow control using RTS/CTS signals. */
215 SP_FLOWCONTROL_RTSCTS = 2,
216 /** Hardware flow control using DTR/DSR signals. */
217 SP_FLOWCONTROL_DTRDSR = 3,
220 /** Input signals. */
222 /** Clear to send. */
224 /** Data set ready. */
226 /** Data carrier detect. */
228 /** Ring indicator. */
234 * An opaque structure representing a serial port.
239 * @struct sp_port_config
240 * An opaque structure representing the configuration for a serial port.
242 struct sp_port_config;
245 * @struct sp_event_set
246 * A set of handles to wait on for events.
248 struct sp_event_set {
249 /** Array of OS-specific handles. */
251 /** Array of bitmasks indicating which events apply for each handle. */
252 enum sp_event *masks;
253 /** Number of handles. */
258 @defgroup Enumeration Port enumeration
263 * Obtain a pointer to a new sp_port structure representing the named port.
265 * The user should allocate a variable of type "struct sp_port *" and pass a
266 * pointer to this to receive the result.
268 * The result should be freed after use by calling sp_free_port().
270 * If any error is returned, the variable pointed to by port_ptr will be set
271 * to NULL. Otherwise, it will be set to point to the newly allocated port.
273 * @return SP_OK upon success, a negative error code otherwise.
275 enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
278 * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port().
280 void sp_free_port(struct sp_port *port);
283 * List the serial ports available on the system.
285 * The result obtained is an array of pointers to sp_port structures,
286 * terminated by a NULL. The user should allocate a variable of type
287 * "struct sp_port **" and pass a pointer to this to receive the result.
289 * The result should be freed after use by calling sp_free_port_list().
290 * If a port from the list is to be used after freeing the list, it must be
291 * copied first using sp_copy_port().
293 * If any error is returned, the variable pointed to by list_ptr will be set
294 * to NULL. Otherwise, it will be set to point to the newly allocated array.
296 * @return SP_OK upon success, a negative error code otherwise.
298 enum sp_return sp_list_ports(struct sp_port ***list_ptr);
301 * Make a new copy of a sp_port structure.
303 * The user should allocate a variable of type "struct sp_port *" and pass a
304 * pointer to this to receive the result.
306 * The copy should be freed after use by calling sp_free_port().
308 * If any error is returned, the variable pointed to by copy_ptr will be set
309 * to NULL. Otherwise, it will be set to point to the newly allocated copy.
311 * @return SP_OK upon success, a negative error code otherwise.
313 enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
316 * Free a port list obtained from sp_list_ports().
318 * This will also free all the sp_port structures referred to from the list;
319 * any that are to be retained must be copied first using sp_copy_port().
321 void sp_free_port_list(struct sp_port **ports);
325 * @defgroup Ports Opening, closing and querying ports
330 * Open the specified serial port.
332 * @param port Pointer to port structure.
333 * @param flags Flags to use when opening the serial port.
335 * @return SP_OK upon success, a negative error code otherwise.
337 enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
340 * Close the specified serial port.
342 * @return SP_OK upon success, a negative error code otherwise.
344 enum sp_return sp_close(struct sp_port *port);
347 * Get the name of a port.
349 * The name returned is whatever is normally used to refer to a port on the
350 * current operating system; e.g. for Windows it will usually be a "COMn"
351 * device name, and for Unix it will be a device path beginning with "/dev/".
353 * @param port Pointer to port structure.
355 * @return The port name, or NULL if an invalid port is passed. The name
356 * string is part of the port structure and may not be used after the
357 * port structure has been freed.
359 char *sp_get_port_name(const struct sp_port *port);
362 * Get the operating system handle for a port.
364 * The type of the handle depends on the operating system. On Unix based
365 * systems, the handle is a file descriptor of type "int". On Windows, the
366 * handle is of type "HANDLE". The user should allocate a variable of the
367 * appropriate type and pass a pointer to this to receive the result.
369 * To obtain a valid handle, the port must first be opened by calling
370 * sp_open() using the same port structure.
372 * After the port is closed or the port structure freed, the handle may
373 * no longer be valid.
375 * @warning This feature is provided so that programs may make use of
376 * OS-specific functionality where desired. Doing so obviously
377 * comes at a cost in portability. It also cannot be guaranteed
378 * that direct usage of the OS handle will not conflict with the
379 * library's own usage of the port. Be careful.
381 * @return SP_OK upon success, a negative error code otherwise.
383 enum sp_return sp_get_port_handle(const struct sp_port *port, void *result_ptr);
387 * @defgroup Configuration Setting port parameters
392 * Allocate a port configuration structure.
394 * The user should allocate a variable of type "struct sp_config *" and pass a
395 * pointer to this to receive the result. The variable will be updated to
396 * point to the new configuration structure. The structure is opaque and must
397 * be accessed via the functions provided.
399 * All parameters in the structure will be initialised to special values which
400 * are ignored by sp_set_config().
402 * The structure should be freed after use by calling sp_free_config().
404 * @param config_ptr Pointer to variable to receive result.
406 * @return SP_OK upon success, a negative error code otherwise.
408 enum sp_return sp_new_config(struct sp_port_config **config_ptr);
411 * Free a port configuration structure.
413 * @param config Pointer to configuration structure.
415 void sp_free_config(struct sp_port_config *config);
418 * Get the current configuration of the specified serial port.
420 * The user should allocate a configuration structure using sp_new_config()
421 * and pass this as the config parameter. The configuration structure will
422 * be updated with the port configuration.
424 * Any parameters that are configured with settings not recognised or
425 * supported by libserialport, will be set to special values that are
426 * ignored by sp_set_config().
428 * @return SP_OK upon success, a negative error code otherwise.
430 enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
433 * Set the configuration for the specified serial port.
435 * For each parameter in the configuration, there is a special value (usually
436 * -1, but see the documentation for each field). These values will be ignored
437 * and the corresponding setting left unchanged on the port.
439 * @return SP_OK upon success, a negative error code otherwise.
441 enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
444 * Set the baud rate for the specified serial port.
446 * @param port Pointer to port structure.
447 * @param baudrate Baud rate in bits per second.
449 * @return SP_OK upon success, a negative error code otherwise.
451 enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate);
454 * Get the baud rate from a port configuration.
456 * The user should allocate a variable of type int and pass a pointer to this
457 * to receive the result.
459 * @param config Pointer to configuration structure.
460 * @param baudrate_ptr Pointer to variable to store result.
462 * @return SP_OK upon success, a negative error code otherwise.
464 enum sp_return sp_get_config_baudrate(const struct sp_port_config *config, int *baudrate_ptr);
467 * Set the baud rate in a port configuration.
469 * @param config Pointer to configuration structure.
470 * @param baudrate Baud rate in bits per second, or -1 to retain current setting.
472 * @return SP_OK upon success, a negative error code otherwise.
474 enum sp_return sp_set_config_baudrate(struct sp_port_config *config, int baudrate);
477 * Set the data bits for the specified serial port.
479 * @param port Pointer to port structure.
480 * @param bits Number of data bits.
482 * @return SP_OK upon success, a negative error code otherwise.
484 enum sp_return sp_set_bits(struct sp_port *port, int bits);
487 * Get the data bits from a port configuration.
489 * The user should allocate a variable of type int and pass a pointer to this
490 * to receive the result.
492 * @param config Pointer to configuration structure.
493 * @param bits_ptr Pointer to variable to store result.
495 * @return SP_OK upon success, a negative error code otherwise.
497 enum sp_return sp_get_config_bits(const struct sp_port_config *config, int *bits_ptr);
500 * Set the data bits in a port configuration.
502 * @param config Pointer to configuration structure.
503 * @param bits Number of data bits, or -1 to retain current setting.
505 * @return SP_OK upon success, a negative error code otherwise.
507 enum sp_return sp_set_config_bits(struct sp_port_config *config, int bits);
510 * Set the parity setting for the specified serial port.
512 * @param port Pointer to port structure.
513 * @param parity Parity setting.
515 * @return SP_OK upon success, a negative error code otherwise.
517 enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity);
520 * Get the parity setting from a port configuration.
522 * The user should allocate a variable of type enum sp_parity and pass a pointer to this
523 * to receive the result.
525 * @param config Pointer to configuration structure.
526 * @param parity_ptr Pointer to variable to store result.
528 * @return SP_OK upon success, a negative error code otherwise.
530 enum sp_return sp_get_config_parity(const struct sp_port_config *config, enum sp_parity *parity_ptr);
533 * Set the parity setting in a port configuration.
535 * @param config Pointer to configuration structure.
536 * @param parity Parity setting, or -1 to retain current setting.
538 * @return SP_OK upon success, a negative error code otherwise.
540 enum sp_return sp_set_config_parity(struct sp_port_config *config, enum sp_parity parity);
543 * Set the stop bits for the specified serial port.
545 * @param port Pointer to port structure.
546 * @param stopbits Number of stop bits.
548 * @return SP_OK upon success, a negative error code otherwise.
550 enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits);
553 * Get the stop bits from a port configuration.
555 * The user should allocate a variable of type int and pass a pointer to this
556 * to receive the result.
558 * @param config Pointer to configuration structure.
559 * @param stopbits_ptr Pointer to variable to store result.
561 * @return SP_OK upon success, a negative error code otherwise.
563 enum sp_return sp_get_config_stopbits(const struct sp_port_config *config, int *stopbits_ptr);
566 * Set the stop bits in a port configuration.
568 * @param config Pointer to configuration structure.
569 * @param stopbits Number of stop bits, or -1 to retain current setting.
571 * @return SP_OK upon success, a negative error code otherwise.
573 enum sp_return sp_set_config_stopbits(struct sp_port_config *config, int stopbits);
576 * Set the RTS pin behaviour for the specified serial port.
578 * @param port Pointer to port structure.
579 * @param rts RTS pin mode.
581 * @return SP_OK upon success, a negative error code otherwise.
583 enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts);
586 * Get the RTS pin behaviour from a port configuration.
588 * The user should allocate a variable of type enum sp_rts and pass a pointer to this
589 * to receive the result.
591 * @param config Pointer to configuration structure.
592 * @param rts_ptr Pointer to variable to store result.
594 * @return SP_OK upon success, a negative error code otherwise.
596 enum sp_return sp_get_config_rts(const struct sp_port_config *config, enum sp_rts *rts_ptr);
599 * Set the RTS pin behaviour in a port configuration.
601 * @param config Pointer to configuration structure.
602 * @param rts RTS pin mode, or -1 to retain current setting.
604 * @return SP_OK upon success, a negative error code otherwise.
606 enum sp_return sp_set_config_rts(struct sp_port_config *config, enum sp_rts rts);
609 * Set the CTS pin behaviour for the specified serial port.
611 * @param port Pointer to port structure.
612 * @param cts CTS pin mode.
614 * @return SP_OK upon success, a negative error code otherwise.
616 enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts);
619 * Get the CTS pin behaviour from a port configuration.
621 * The user should allocate a variable of type enum sp_cts and pass a pointer to this
622 * to receive the result.
624 * @param config Pointer to configuration structure.
625 * @param cts_ptr Pointer to variable to store result.
627 * @return SP_OK upon success, a negative error code otherwise.
629 enum sp_return sp_get_config_cts(const struct sp_port_config *config, enum sp_cts *cts_ptr);
632 * Set the CTS pin behaviour in a port configuration.
634 * @param config Pointer to configuration structure.
635 * @param cts CTS pin mode, or -1 to retain current setting.
637 * @return SP_OK upon success, a negative error code otherwise.
639 enum sp_return sp_set_config_cts(struct sp_port_config *config, enum sp_cts cts);
642 * Set the DTR pin behaviour for the specified serial port.
644 * @param port Pointer to port structure.
645 * @param dtr DTR pin mode.
647 * @return SP_OK upon success, a negative error code otherwise.
649 enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr);
652 * Get the DTR pin behaviour from a port configuration.
654 * The user should allocate a variable of type enum sp_dtr and pass a pointer to this
655 * to receive the result.
657 * @param config Pointer to configuration structure.
658 * @param dtr_ptr Pointer to variable to store result.
660 * @return SP_OK upon success, a negative error code otherwise.
662 enum sp_return sp_get_config_dtr(const struct sp_port_config *config, enum sp_dtr *dtr_ptr);
665 * Set the DTR pin behaviour in a port configuration.
667 * @param config Pointer to configuration structure.
668 * @param dtr DTR pin mode, or -1 to retain current setting.
670 * @return SP_OK upon success, a negative error code otherwise.
672 enum sp_return sp_set_config_dtr(struct sp_port_config *config, enum sp_dtr dtr);
675 * Set the DSR pin behaviour for the specified serial port.
677 * @param port Pointer to port structure.
678 * @param dsr DSR pin mode.
680 * @return SP_OK upon success, a negative error code otherwise.
682 enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr);
685 * Get the DSR pin behaviour from a port configuration.
687 * The user should allocate a variable of type enum sp_dsr and pass a pointer to this
688 * to receive the result.
690 * @param config Pointer to configuration structure.
691 * @param dsr_ptr Pointer to variable to store result.
693 * @return SP_OK upon success, a negative error code otherwise.
695 enum sp_return sp_get_config_dsr(const struct sp_port_config *config, enum sp_dsr *dsr_ptr);
698 * Set the DSR pin behaviour in a port configuration.
700 * @param config Pointer to configuration structure.
701 * @param dsr DSR pin mode, or -1 to retain current setting.
703 * @return SP_OK upon success, a negative error code otherwise.
705 enum sp_return sp_set_config_dsr(struct sp_port_config *config, enum sp_dsr dsr);
708 * Set the XON/XOFF configuration for the specified serial port.
710 * @param port Pointer to port structure.
711 * @param xon_xoff XON/XOFF mode.
713 * @return SP_OK upon success, a negative error code otherwise.
715 enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
718 * Get the XON/XOFF configuration from a port configuration.
720 * The user should allocate a variable of type enum sp_xonxoff and pass a pointer to this
721 * to receive the result.
723 * @param config Pointer to configuration structure.
724 * @param xon_xoff_ptr Pointer to variable to store result.
726 * @return SP_OK upon success, a negative error code otherwise.
728 enum sp_return sp_get_config_xon_xoff(const struct sp_port_config *config, enum sp_xonxoff *xon_xoff_ptr);
731 * Set the XON/XOFF configuration in a port configuration.
733 * @param config Pointer to configuration structure.
734 * @param xon_xoff XON/XOFF mode, or -1 to retain current setting.
736 * @return SP_OK upon success, a negative error code otherwise.
738 enum sp_return sp_set_config_xon_xoff(struct sp_port_config *config, enum sp_xonxoff xon_xoff);
741 * Set the flow control type in a port configuration.
743 * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
744 * XON/XOFF settings as necessary for the specified flow control
745 * type. For more fine-grained control of these settings, use their
746 * individual configuration functions.
748 * @param config Pointer to configuration structure.
749 * @param flowcontrol Flow control setting to use.
751 * @return SP_OK upon success, a negative error code otherwise.
753 enum sp_return sp_set_config_flowcontrol(struct sp_port_config *config, enum sp_flowcontrol flowcontrol);
756 * Set the flow control type for the specified serial port.
758 * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
759 * XON/XOFF settings as necessary for the specified flow control
760 * type. For more fine-grained control of these settings, use their
761 * individual configuration functions.
763 * @param port Pointer to port structure.
764 * @param flowcontrol Flow control setting to use.
766 * @return SP_OK upon success, a negative error code otherwise.
768 enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
772 * @defgroup Data Reading, writing, and flushing data
777 * Read bytes from the specified serial port, blocking until complete.
779 * @warning If your program runs on Unix, defines its own signal handlers, and
780 * needs to abort blocking reads when these are called, then you
781 * should not use this function. It repeats system calls that return
782 * with EINTR. To be able to abort a read from a signal handler, you
783 * should implement your own blocking read using sp_nonblocking_read()
784 * together with a blocking method that makes sense for your program.
785 * E.g. you can obtain the file descriptor for an open port using
786 * sp_get_port_handle() and use this to call select() or pselect(),
787 * with appropriate arrangements to return if a signal is received.
789 * @param port Pointer to port structure.
790 * @param buf Buffer in which to store the bytes read.
791 * @param count Requested number of bytes to read.
792 * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
794 * @return The number of bytes read on success, or a negative error code. If
795 * the number of bytes returned is less than that requested, the
796 * timeout was reached before the requested number of bytes was
797 * available. If timeout is zero, the function will always return
798 * either the requested number of bytes or a negative error code.
800 enum sp_return sp_blocking_read(struct sp_port *port, void *buf, size_t count, unsigned int timeout);
803 * Read bytes from the specified serial port, without blocking.
805 * @param port Pointer to port structure.
806 * @param buf Buffer in which to store the bytes read.
807 * @param count Maximum number of bytes to read.
809 * @return The number of bytes read on success, or a negative error code. The
810 * number of bytes returned may be any number from zero to the maximum
811 * that was requested.
813 enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf, size_t count);
816 * Write bytes to the specified serial port, blocking until complete.
818 * Note that this function only ensures that the accepted bytes have been
819 * written to the OS; they may be held in driver or hardware buffers and not
820 * yet physically transmitted. To check whether all written bytes have actually
821 * been transmitted, use the sp_output_waiting() function. To wait until all
822 * written bytes have actually been transmitted, use the sp_drain() function.
824 * @warning If your program runs on Unix, defines its own signal handlers, and
825 * needs to abort blocking writes when these are called, then you
826 * should not use this function. It repeats system calls that return
827 * with EINTR. To be able to abort a write from a signal handler, you
828 * should implement your own blocking write using sp_nonblocking_write()
829 * together with a blocking method that makes sense for your program.
830 * E.g. you can obtain the file descriptor for an open port using
831 * sp_get_port_handle() and use this to call select() or pselect(),
832 * with appropriate arrangements to return if a signal is received.
834 * @param port Pointer to port structure.
835 * @param buf Buffer containing the bytes to write.
836 * @param count Requested number of bytes to write.
837 * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
839 * @return The number of bytes written on success, or a negative error code.
840 * If the number of bytes returned is less than that requested, the
841 * timeout was reached before the requested number of bytes was
842 * written. If timeout is zero, the function will always return
843 * either the requested number of bytes or a negative error code. In
844 * the event of an error there is no way to determine how many bytes
845 * were sent before the error occured.
847 enum sp_return sp_blocking_write(struct sp_port *port, const void *buf, size_t count, unsigned int timeout);
850 * Write bytes to the specified serial port, without blocking.
852 * Note that this function only ensures that the accepted bytes have been
853 * written to the OS; they may be held in driver or hardware buffers and not
854 * yet physically transmitted. To check whether all written bytes have actually
855 * been transmitted, use the sp_output_waiting() function. To wait until all
856 * written bytes have actually been transmitted, use the sp_drain() function.
858 * @param port Pointer to port structure.
859 * @param buf Buffer containing the bytes to write.
860 * @param count Maximum number of bytes to write.
862 * @return The number of bytes written on success, or a negative error code.
863 * The number of bytes returned may be any number from zero to the
864 * maximum that was requested.
866 enum sp_return sp_nonblocking_write(struct sp_port *port, const void *buf, size_t count);
869 * Gets the number of bytes waiting in the input buffer.
871 * @param port Pointer to port structure.
873 * @return Number of bytes waiting on success, a negative error code otherwise.
875 enum sp_return sp_input_waiting(struct sp_port *port);
878 * Gets the number of bytes waiting in the output buffer.
880 * @param port Pointer to port structure.
882 * @return Number of bytes waiting on success, a negative error code otherwise.
884 enum sp_return sp_output_waiting(struct sp_port *port);
887 * Flush serial port buffers. Data in the selected buffer(s) is discarded.
889 * @param port Pointer to port structure.
890 * @param buffers Which buffer(s) to flush.
892 * @return SP_OK upon success, a negative error code otherwise.
894 enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
897 * Wait for buffered data to be transmitted.
899 * @warning If your program runs on Unix, defines its own signal handlers, and
900 * needs to abort draining the output buffer when when these are
901 * called, then you should not use this function. It repeats system
902 * calls that return with EINTR. To be able to abort a drain from a
903 * signal handler, you would need to implement your own blocking
904 * drain by polling the result of sp_output_waiting().
906 * @param port Pointer to port structure.
908 * @return SP_OK upon success, a negative error code otherwise.
910 enum sp_return sp_drain(struct sp_port *port);
914 * @defgroup Waiting Waiting for events
919 * Allocate storage for a set of events.
921 * The user should allocate a variable of type struct sp_event_set *,
922 * then pass a pointer to this variable to receive the result.
924 * The result should be freed after use by calling sp_free_event_set().
926 * @return SP_OK upon success, a negative error code otherwise.
928 enum sp_return sp_new_event_set(struct sp_event_set **result_ptr);
931 * Add events to a struct sp_event_set for a given port.
933 * The port must first be opened by calling sp_open() using the same port
936 * After the port is closed or the port structure freed, the results may
937 * no longer be valid.
939 * @param event_set Event set to update.
940 * @param port Pointer to port structure.
941 * @param mask Bitmask of events to be waited for.
943 * @return SP_OK upon success, a negative error code otherwise.
945 enum sp_return sp_add_port_events(struct sp_event_set *event_set,
946 const struct sp_port *port, enum sp_event mask);
949 * Wait for any of a set of events to occur.
951 * @param event_set Event set to wait on.
952 * @param timeout Timeout in milliseconds, or zero to wait indefinitely.
954 * @return SP_OK upon success, a negative error code otherwise.
956 enum sp_return sp_wait(struct sp_event_set *event_set, unsigned int timeout);
959 * Free a structure allocated by sp_new_event_set().
961 void sp_free_event_set(struct sp_event_set *event_set);
965 * @defgroup Signals Port signalling operations
970 * Gets the status of the control signals for the specified port.
972 * The user should allocate a variable of type "enum sp_signal" and pass a
973 * pointer to this variable to receive the result. The result is a bitmask
974 * in which individual signals can be checked by bitwise OR with values of
975 * the sp_signal enum.
977 * @param port Pointer to port structure.
978 * @param signals Pointer to variable to receive result.
980 * @return SP_OK upon success, a negative error code otherwise.
982 enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals);
985 * Put the port transmit line into the break state.
987 * @param port Pointer to port structure.
989 * @return SP_OK upon success, a negative error code otherwise.
991 enum sp_return sp_start_break(struct sp_port *port);
994 * Take the port transmit line out of the break state.
996 * @param port Pointer to port structure.
998 * @return SP_OK upon success, a negative error code otherwise.
1000 enum sp_return sp_end_break(struct sp_port *port);
1004 * @defgroup Errors Obtaining error information
1009 * Get the error code for a failed operation.
1011 * In order to obtain the correct result, this function should be called
1012 * straight after the failure, before executing any other system operations.
1014 * @return The system's numeric code for the error that caused the last
1015 * operation to fail.
1017 int sp_last_error_code(void);
1020 * Get the error message for a failed operation.
1022 * In order to obtain the correct result, this function should be called
1023 * straight after the failure, before executing other system operations.
1025 * @return The system's message for the error that caused the last
1026 * operation to fail. This string may be allocated by the function,
1027 * and should be freed after use by calling sp_free_error_message().
1029 char *sp_last_error_message(void);
1032 * Free an error message returned by sp_last_error_message().
1034 void sp_free_error_message(char *message);
1037 * Set the handler function for library debugging messages.
1039 * Debugging messages are generated by the library during each operation,
1040 * to help in diagnosing problems. The handler will be called for each
1041 * message. The handler can be set to NULL to ignore all debug messages.
1043 * The handler function should accept a format string and variable length
1044 * argument list, in the same manner as e.g. printf().
1046 * The default handler is sp_default_debug_handler().
1048 void sp_set_debug_handler(void (*handler)(const char *format, ...));
1051 * Default handler function for library debugging messages.
1053 * This function prints debug messages to the standard error stream if the
1054 * environment variable LIBSERIALPORT_DEBUG is set. Otherwise, they are
1057 void sp_default_debug_handler(const char *format, ...);
1062 * @defgroup Versions Version number querying functions, definitions, and macros
1064 * This set of API calls returns two different version numbers related
1065 * to libserialport. The "package version" is the release version number of the
1066 * libserialport tarball in the usual "major.minor.micro" format, e.g. "0.1.0".
1068 * The "library version" is independent of that; it is the libtool version
1069 * number in the "current:revision:age" format, e.g. "2:0:0".
1070 * See http://www.gnu.org/software/libtool/manual/libtool.html#Libtool-versioning for details.
1072 * Both version numbers (and/or individual components of them) can be
1073 * retrieved via the API calls at runtime, and/or they can be checked at
1074 * compile/preprocessor time using the respective macros.
1080 * Package version macros (can be used for conditional compilation).
1083 /** The libserialport package 'major' version number. */
1084 #define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@
1086 /** The libserialport package 'minor' version number. */
1087 #define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@
1089 /** The libserialport package 'micro' version number. */
1090 #define SP_PACKAGE_VERSION_MICRO @SP_PACKAGE_VERSION_MICRO@
1092 /** The libserialport package version ("major.minor.micro") as string. */
1093 #define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@"
1096 * Library/libtool version macros (can be used for conditional compilation).
1099 /** The libserialport libtool 'current' version number. */
1100 #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@
1102 /** The libserialport libtool 'revision' version number. */
1103 #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@
1105 /** The libserialport libtool 'age' version number. */
1106 #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@
1108 /** The libserialport libtool version ("current:revision:age") as string. */
1109 #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@"
1112 * Get the major libserialport package version number.
1114 * @return The major package version number.
1118 int sp_get_major_package_version(void);
1121 * Get the minor libserialport package version number.
1123 * @return The minor package version number.
1127 int sp_get_minor_package_version(void);
1130 * Get the micro libserialport package version number.
1132 * @return The micro package version number.
1136 int sp_get_micro_package_version(void);
1139 * Get the libserialport package version number as a string.
1141 * @return The package version number string. The returned string is
1142 * static and thus should NOT be free'd by the caller.
1146 const char *sp_get_package_version_string(void);
1149 * Get the "current" part of the libserialport library version number.
1151 * @return The "current" library version number.
1155 int sp_get_current_lib_version(void);
1158 * Get the "revision" part of the libserialport library version number.
1160 * @return The "revision" library version number.
1164 int sp_get_revision_lib_version(void);
1167 * Get the "age" part of the libserialport library version number.
1169 * @return The "age" library version number.
1173 int sp_get_age_lib_version(void);
1176 * Get the libserialport library version number as a string.
1178 * @return The library version number string. The returned string is
1179 * static and thus should NOT be free'd by the caller.
1183 const char *sp_get_lib_version_string(void);