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.)
40 * libserialport is an open source project released under the LGPL3+ license.
45 * The API is simple, and designed to be a minimal wrapper around the serial
46 * port support in each OS.
48 * Most functions take a pointer to a struct sp_port, which represents a serial
49 * port. These structures are always allocated and freed by the library, using
50 * the functions in the @ref Enumeration "Enumeration" section.
52 * All functions can return only three possible error values. @ref SP_ERR_ARG
53 * indicates the function was called with invalid arguments. @ref SP_ERR_FAIL
54 * indicates that the OS reported a failure. @ref SP_ERR_MEM indicates that a
55 * memory allocation failed. All of these error values are negative.
57 * When @ref SP_ERR_FAIL is returned, an error code or string description of
58 * the error can be obtained by calling sp_last_error_code() or
59 * sp_last_error_message(). The error code or message is that provided by the
60 * OS; libserialport does not define any error codes or messages of its own.
62 * Function calls that succeed return @ref SP_OK, which is equal to zero,
63 * or where otherwise documented a positive value.
66 #ifndef LIBSERIALPORT_LIBSERIALPORT_H
67 #define LIBSERIALPORT_LIBSERIALPORT_H
78 /* Package version macros (e.g. for conditional compilation). */
79 #define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@
80 #define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@
81 #define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@"
83 /* Library/libtool version macros (e.g. for conditional compilation). */
84 #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@
85 #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@
86 #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@
87 #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@"
91 /** Operation completed successfully. */
93 /** Invalid arguments were passed to the function. */
95 /** A system error occured while executing the operation. */
97 /** A memory allocation failed while executing the operation. */
101 /** Port access modes. */
103 /** Open port for read access. */
105 /** Open port for write access. */
107 /** Open port in non-blocking mode. */
108 SP_MODE_NONBLOCK = 4,
111 /** Buffer selection. */
115 /** Output buffer. */
121 /** Parity settings. */
123 /** Special value to indicate setting should be left alone. */
124 SP_PARITY_INVALID = -1,
133 /** RTS pin behaviour. */
135 /** Special value to indicate setting should be left alone. */
141 /** RTS used for flow control. */
142 SP_RTS_FLOW_CONTROL = 2,
145 /** CTS pin behaviour. */
147 /** Special value to indicate setting should be left alone. */
151 /** CTS used for flow control. */
152 SP_CTS_FLOW_CONTROL = 1,
155 /** DTR pin behaviour. */
157 /** Special value to indicate setting should be left alone. */
163 /** DTR used for flow control. */
164 SP_DTR_FLOW_CONTROL = 2,
167 /** DSR pin behaviour. */
169 /** Special value to indicate setting should be left alone. */
173 /** DSR used for flow control. */
174 SP_DSR_FLOW_CONTROL = 1,
177 /** XON/XOFF flow control behaviour. */
179 /** Special value to indicate setting should be left alone. */
180 SP_XONXOFF_INVALID = -1,
181 /** XON/XOFF disabled. */
182 SP_XONXOFF_DISABLED = 0,
183 /** XON/XOFF enabled for input only. */
185 /** XON/XOFF enabled for output only. */
187 /** XON/XOFF enabled for input and output. */
188 SP_XONXOFF_INOUT = 3,
191 /** Standard flow control combinations. */
192 enum sp_flowcontrol {
193 /** No flow control. */
194 SP_FLOWCONTROL_NONE = 0,
195 /** Software flow control using XON/XOFF characters. */
196 SP_FLOWCONTROL_XONXOFF = 1,
197 /** Hardware flow control using RTS/CTS signals. */
198 SP_FLOWCONTROL_RTSCTS = 2,
199 /** Hardware flow control using DTR/DSR signals. */
200 SP_FLOWCONTROL_DTRDSR = 3,
203 /** Input signals. */
205 /** Clear to send. */
207 /** Data set ready. */
209 /** Data carrier detect. */
211 /** Ring indicator. */
215 /** A serial port. */
217 /** Name used to open the port. */
220 /** OS-specific port handle. */
229 /** Configuration for a serial port. */
230 struct sp_port_config {
231 /** Baud rate in bits per second. */
233 /** Number of data bits to use. Valid values are 5 to 8. */
235 /** Parity setting to use. */
236 enum sp_parity parity;
237 /** Number of stop bits to use (1 or 2). */
247 /** XON/XOFF flow control mode. */
248 enum sp_xonxoff xon_xoff;
252 @defgroup Enumeration Port enumeration
257 * Obtain a pointer to a new sp_port structure representing the named port.
259 * The user should allocate a variable of type "struct sp_port *" and pass a
260 * pointer to this to receive the result.
262 * The result should be freed after use by calling sp_free_port().
264 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
265 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
266 * is returned, the variable pointed to by port_ptr will be set to NULL.
267 * Otherwise, it will be set to point to the newly allocated port.
269 enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
272 * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port().
274 void sp_free_port(struct sp_port *port);
277 * List the serial ports available on the system.
279 * The result obtained is an array of pointers to sp_port structures,
280 * terminated by a NULL. The user should allocate a variable of type
281 * "struct sp_port **" and pass a pointer to this to receive the result.
283 * The result should be freed after use by calling sp_free_port_list().
284 * If a port from the list is to be used after freeing the list, it must be
285 * copied first using sp_copy_port().
287 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
288 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
289 * is returned, the variable pointed to by list_ptr will be set to NULL.
290 * Otherwise, it will be set to point to the newly allocated array.
292 enum sp_return sp_list_ports(struct sp_port ***list_ptr);
295 * Make a new copy of a sp_port structure.
297 * The user should allocate a variable of type "struct sp_port *" and pass a
298 * pointer to this to receive the result.
300 * The copy should be freed after use by calling sp_free_port().
302 * @return SP_OK on success, SP_ERR_MEM on allocation failure, or SP_ERR_ARG
303 * if an invalid port or pointer is passed. If any error is returned,
304 * the variable pointed to by copy_ptr will be set to NULL. Otherwise,
305 * it will be set to point to the newly allocated copy.
307 enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
310 * Free a port list obtained from sp_list_ports().
312 * This will also free all the sp_port structures referred to from the list;
313 * any that are to be retained must be copied first using sp_copy_port().
315 void sp_free_port_list(struct sp_port **ports);
319 * @defgroup Ports Opening and closing ports
324 * Open the specified serial port.
326 * @param port Pointer to port structure.
327 * @param flags Flags to use when opening the serial port.
329 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
330 * failure, or SP_ERR_ARG if an invalid port is passed.
332 enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
335 * Close the specified serial port.
337 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
338 * if an invalid port is passed.
340 enum sp_return sp_close(struct sp_port *port);
344 * @defgroup Configuration Setting port parameters
349 * Get the current configuration of the specified serial port.
351 * The user should allocate a struct sp_port_config, then pass a pointer to it
352 * as the config parameter. The struct will be populated with the port
355 * Any setting that is in a state not recognised or supported by
356 * libserialport will have its value set to -1 in the struct.
358 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
359 * for invalid arguments.
361 enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
364 * Set the configuration for the specified serial port.
366 * The user should populate a struct sp_port_config, then pass a pointer to it
367 * as the config parameter.
369 * To retain the current value of any setting, set that field to -1.
371 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
372 * for invalid arguments.
374 enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
377 * Set the baud rate for the specified serial port.
379 * @param port Pointer to port structure.
380 * @param baudrate Baud rate in bits per second.
382 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
383 * for invalid arguments.
385 enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate);
388 * Set the number of data bits for the specified serial port.
390 * @param port Pointer to port structure.
391 * @param bits Number of data bits to use. Valid values are 5 to 8.
393 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
394 * for invalid arguments.
396 enum sp_return sp_set_bits(struct sp_port *port, int bits);
399 * Set the parity for the specified serial port.
401 * @param port Pointer to port structure.
402 * @param parity Parity setting to use.
404 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
405 * for invalid arguments.
407 enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity);
410 * Set the number of stop bits for the specified port.
412 * @param port Pointer to port structure.
413 * @param stopbits Number of stop bits to use (1 or 2).
415 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
416 * for invalid arguments.
418 enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits);
421 * Set the flow control type for the specified serial port.
423 * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
424 * XON/XOFF settings as necessary for the specified flow control
425 * type. For more fine-grained control of these settings, use their
426 * individual configuration functions or the sp_set_config() function.
428 * @param port Pointer to port structure.
429 * @param flowcontrol Flow control setting to use.
431 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
432 * for invalid arguments.
434 enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
437 * Set the RTS pin behaviour for the specified port.
439 * @param port Pointer to port structure.
440 * @param rts RTS pin mode.
442 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
443 * for invalid arguments.
445 enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts);
448 * Set the CTS pin behaviour for the specified port.
450 * @param port Pointer to port structure.
451 * @param cts CTS pin mode.
453 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
454 * for invalid arguments.
456 enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts);
459 * Set the DTR pin behaviour for the specified port.
461 * @param port Pointer to port structure.
462 * @param dtr DTR pin mode.
464 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
465 * for invalid arguments.
467 enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr);
470 * Set the RTS pin behaviour for the specified port.
472 * @param port Pointer to port structure.
473 * @param dsr DSR pin mode.
475 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
476 * for invalid arguments.
478 enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr);
481 * Configure XON/XOFF flow control for the specified port.
483 * @param port Pointer to port structure.
484 * @param xon_xoff XON/XOFF flow control mode.
486 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
487 * for invalid arguments.
489 enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
493 * @defgroup Data Reading, writing, and flushing data
498 * Read bytes from the specified serial port.
500 * Note that this function may return after reading less than the specified
501 * number of bytes; it is the user's responsibility to iterate as necessary
504 * @param port Pointer to port structure.
505 * @param buf Buffer in which to store the bytes read.
506 * @param count Maximum number of bytes to read.
508 * @return The number of bytes read, SP_ERR_FAIL on failure,
509 * or SP_ERR_ARG for invalid arguments.
511 enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
514 * Write bytes to the specified serial port.
516 * Note that this function may return after writing less than the specified
517 * number of bytes; it is the user's responsibility to iterate as necessary
520 * @param port Pointer to port structure.
521 * @param buf Buffer containing the bytes to write.
522 * @param count Maximum number of bytes to write.
524 * @return The number of bytes written, SP_ERR_FAIL on failure,
525 * or SP_ERR_ARG for invalid arguments.
527 enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
530 * Flush serial port buffers. Data in the selected buffer(s) is discarded.
532 * @param port Pointer to port structure.
533 * @param buffers Which buffer(s) to flush.
535 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
536 * if an invalid port is passed.
538 enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
541 * Wait for buffered data to be transmitted.
543 * @param port Pointer to port structure.
545 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
546 * if an invalid port is passed.
548 enum sp_return sp_drain(struct sp_port *port);
552 * @defgroup Signal Port signalling operations
557 * Gets the status of the control signals for the specified port.
559 * The user should allocate a variable of type "enum sp_signal" and pass a
560 * pointer to this variable to receive the result. The result is a bitmask
561 * in which individual signals can be checked by bitwise OR with values of
562 * the sp_signal enum.
564 * @param port Pointer to port structure.
565 * @param signals Pointer to variable to receive result.
567 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
568 * if an an invalid port or pointer is passed.
570 enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals);
573 * Put the port transmit line into the break state.
575 * @param port Pointer to port structure.
577 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
578 * if an invalid port is passed.
580 enum sp_return sp_start_break(struct sp_port *port);
583 * Take the port transmit line out of the break state.
585 * @param port Pointer to port structure.
587 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
588 * if an invalid port is passed.
590 enum sp_return sp_end_break(struct sp_port *port);
594 * @defgroup Errors Obtaining error information
599 * Get the error code for a failed operation.
601 * In order to obtain the correct result, this function should be called
602 * straight after the failure, before executing any other system operations.
604 * @return The system's numeric code for the error that caused the last
607 int sp_last_error_code(void);
610 * Get the error message for a failed operation.
612 * In order to obtain the correct result, this function should be called
613 * straight after the failure, before executing other system operations.
615 * @return The system's message for the error that caused the last
616 * operation to fail. This string may be allocated by the function,
617 * and should be freed after use by calling sp_free_error_message().
619 char *sp_last_error_message(void);
622 * Free an error message returned by sp_last_error_message().
624 void sp_free_error_message(char *message);