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/>.
22 * @mainpage libserialport API
27 * libserialport is a minimal library written in C that is intended to take
28 * care of the OS-specific details when writing software that uses serial ports.
30 * By writing your serial code to use libserialport, you enable it to work
31 * transparently on any platform supported by the library.
33 * The operations that are supported are:
35 * - @ref Enumeration (obtaining a list of serial ports on the system)
37 * - @ref Configuration (baud rate, parity, etc.)
41 * libserialport is an open source project released under the LGPL3+ license.
46 * The API is simple, and designed to be a minimal wrapper around the serial
47 * port support in each OS.
49 * Most functions take a pointer to a struct sp_port, which represents a serial
50 * port. These structures are always allocated and freed by the library, using
51 * the functions in the @ref Enumeration "Enumeration" section.
53 * All functions can return only three possible error values. @ref SP_ERR_ARG
54 * indicates the function was called with invalid arguments. @ref SP_ERR_FAIL
55 * indicates that the OS reported a failure. @ref SP_ERR_MEM indicates that a
56 * memory allocation failed. All of these error values are negative.
58 * When @ref SP_ERR_FAIL is returned, an error code or string description of
59 * the error can be obtained by calling sp_last_error_code() or
60 * sp_last_error_message(). The error code or message is that provided by the
61 * OS; libserialport does not define any error codes or messages of its own.
63 * Function calls that succeed return @ref SP_OK, which is equal to zero,
64 * or where otherwise documented a positive value.
67 #ifndef LIBSERIALPORT_H
68 #define LIBSERIALPORT_H
79 /* Package version macros (e.g. for conditional compilation). */
80 #define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@
81 #define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@
82 #define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@"
84 /* Library/libtool version macros (e.g. for conditional compilation). */
85 #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@
86 #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@
87 #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@
88 #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@"
92 /** Operation completed successfully. */
94 /** Invalid arguments were passed to the function. */
96 /** A system error occured while executing the operation. */
98 /** A memory allocation failed while executing the operation. */
102 /** Port access modes. */
104 /** Open port for read access. */
106 /** Open port for write access. */
108 /** Open port in non-blocking mode. */
109 SP_MODE_NONBLOCK = 4,
112 /** Buffer selection. */
116 /** Output buffer. */
122 /** Parity settings. */
124 /** Special value to indicate setting should be left alone. */
125 SP_PARITY_INVALID = -1,
134 /** RTS pin behaviour. */
136 /** Special value to indicate setting should be left alone. */
142 /** RTS used for flow control. */
143 SP_RTS_FLOW_CONTROL = 2,
146 /** CTS pin behaviour. */
148 /** Special value to indicate setting should be left alone. */
152 /** CTS used for flow control. */
153 SP_CTS_FLOW_CONTROL = 1,
156 /** DTR pin behaviour. */
158 /** Special value to indicate setting should be left alone. */
164 /** DTR used for flow control. */
165 SP_DTR_FLOW_CONTROL = 2,
168 /** DSR pin behaviour. */
170 /** Special value to indicate setting should be left alone. */
174 /** DSR used for flow control. */
175 SP_DSR_FLOW_CONTROL = 1,
178 /** XON/XOFF flow control behaviour. */
180 /** Special value to indicate setting should be left alone. */
181 SP_XONXOFF_INVALID = -1,
182 /** XON/XOFF disabled. */
183 SP_XONXOFF_DISABLED = 0,
184 /** XON/XOFF enabled for input only. */
186 /** XON/XOFF enabled for output only. */
188 /** XON/XOFF enabled for input and output. */
189 SP_XONXOFF_INOUT = 3,
192 /** Standard flow control combinations. */
193 enum sp_flowcontrol {
194 /** No flow control. */
195 SP_FLOWCONTROL_NONE = 0,
196 /** Software flow control using XON/XOFF characters. */
197 SP_FLOWCONTROL_XONXOFF = 1,
198 /** Hardware flow control using RTS/CTS signals. */
199 SP_FLOWCONTROL_RTSCTS = 2,
200 /** Hardware flow control using DTR/DSR signals. */
201 SP_FLOWCONTROL_DTRDSR = 3,
204 /** A serial port. */
206 /** Name used to open the port. */
209 /** OS-specific port handle. */
218 /** Configuration for a serial port. */
219 struct sp_port_config {
220 /** Baud rate in bits per second. */
222 /** Number of data bits to use. Valid values are 5 to 8. */
224 /** Parity setting to use. */
225 enum sp_parity parity;
226 /** Number of stop bits to use (1 or 2). */
236 /** XON/XOFF flow control mode. */
237 enum sp_xonxoff xon_xoff;
241 @defgroup Enumeration Port enumeration
246 * Obtain a pointer to a new sp_port structure representing the named port.
248 * The user should allocate a variable of type "struct sp_port *" and pass a
249 * pointer to this to receive the result.
251 * The result should be freed after use by calling sp_free_port().
253 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
254 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
255 * is returned, the variable pointed to by port_ptr will be set to NULL.
256 * Otherwise, it will be set to point to the newly allocated port.
258 enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
261 * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port().
263 void sp_free_port(struct sp_port *port);
266 * List the serial ports available on the system.
268 * The result obtained is an array of pointers to sp_port structures,
269 * terminated by a NULL. The user should allocate a variable of type
270 * "struct sp_port **" and pass a pointer to this to receive the result.
272 * The result should be freed after use by calling sp_free_port_list().
273 * If a port from the list is to be used after freeing the list, it must be
274 * copied first using sp_copy_port().
276 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
277 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
278 * is returned, the variable pointed to by list_ptr will be set to NULL.
279 * Otherwise, it will be set to point to the newly allocated array.
281 enum sp_return sp_list_ports(struct sp_port ***list_ptr);
284 * Make a new copy of a sp_port structure.
286 * The user should allocate a variable of type "struct sp_port *" and pass a
287 * pointer to this to receive the result.
289 * The copy should be freed after use by calling sp_free_port().
291 * @return SP_OK on success, SP_ERR_MEM on allocation failure, or SP_ERR_ARG
292 * if an invalid port or pointer is passed. If any error is returned,
293 * the variable pointed to by copy_ptr will be set to NULL. Otherwise,
294 * it will be set to point to the newly allocated copy.
296 enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
299 * Free a port list obtained from sp_list_ports().
301 * This will also free all the sp_port structures referred to from the list;
302 * any that are to be retained must be copied first using sp_copy_port().
304 void sp_free_port_list(struct sp_port **ports);
308 * @defgroup Ports Opening and closing ports
313 * Open the specified serial port.
315 * @param port Pointer to port structure.
316 * @param flags Flags to use when opening the serial port.
318 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
319 * failure, or SP_ERR_ARG if an invalid port is passed.
321 enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
324 * Close the specified serial port.
326 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
327 * if an invalid port is passed.
329 enum sp_return sp_close(struct sp_port *port);
333 * @defgroup Configuration Setting port parameters
338 * Get the current configuration of the specified serial port.
340 * The user should allocate a struct sp_port_config, then pass a pointer to it
341 * as the config parameter. The struct will be populated with the port
344 * Any setting that is in a state not recognised or supported by
345 * libserialport will have its value set to -1 in the struct.
347 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
348 * for invalid arguments.
350 enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
353 * Set the configuration for the specified serial port.
355 * The user should populate a struct sp_port_config, then pass a pointer to it
356 * as the config parameter.
358 * To retain the current value of any setting, set that field to -1.
360 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
361 * for invalid arguments.
363 enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
366 * Set the baud rate for the specified serial port.
368 * @param port Pointer to port structure.
369 * @param baudrate Baud rate in bits per second.
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_baudrate(struct sp_port *port, int baudrate);
377 * Set the number of data bits for the specified serial port.
379 * @param port Pointer to port structure.
380 * @param bits Number of data bits to use. Valid values are 5 to 8.
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_bits(struct sp_port *port, int bits);
388 * Set the parity for the specified serial port.
390 * @param port Pointer to port structure.
391 * @param parity Parity setting to use.
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_parity(struct sp_port *port, enum sp_parity parity);
399 * Set the number of stop bits for the specified port.
401 * @param port Pointer to port structure.
402 * @param stopbits Number of stop bits to use (1 or 2).
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_stopbits(struct sp_port *port, int stopbits);
410 * Set the flow control type for the specified serial port.
412 * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
413 * XON/XOFF settings as necessary for the specified flow control
414 * type. For more fine-grained control of these settings, use their
415 * individual configuration functions or the sp_set_config() function.
417 * @param port Pointer to port structure.
418 * @param flowcontrol Flow control setting to use.
420 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
421 * for invalid arguments.
423 enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
426 * Set the RTS pin behaviour for the specified port.
428 * @param port Pointer to port structure.
429 * @param rts RTS pin mode.
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_rts(struct sp_port *port, enum sp_rts rts);
437 * Set the CTS pin behaviour for the specified port.
439 * @param port Pointer to port structure.
440 * @param cts CTS 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_cts(struct sp_port *port, enum sp_cts cts);
448 * Set the DTR pin behaviour for the specified port.
450 * @param port Pointer to port structure.
451 * @param dtr DTR 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_dtr(struct sp_port *port, enum sp_dtr dtr);
459 * Set the RTS pin behaviour for the specified port.
461 * @param port Pointer to port structure.
462 * @param dsr DSR 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_dsr(struct sp_port *port, enum sp_dsr dsr);
470 * Configure XON/XOFF flow control for the specified port.
472 * @param port Pointer to port structure.
473 * @param xon_xoff XON/XOFF flow control 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_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
482 * @defgroup Data Reading, writing, and flushing data
487 * Read bytes from the specified serial port.
489 * Note that this function may return after reading less than the specified
490 * number of bytes; it is the user's responsibility to iterate as necessary
493 * @param port Pointer to port structure.
494 * @param buf Buffer in which to store the bytes read.
495 * @param count Maximum number of bytes to read.
497 * @return The number of bytes read, SP_ERR_FAIL on failure,
498 * or SP_ERR_ARG for invalid arguments.
500 enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
503 * Write bytes to the specified serial port.
505 * Note that this function may return after writing less than the specified
506 * number of bytes; it is the user's responsibility to iterate as necessary
509 * @param port Pointer to port structure.
510 * @param buf Buffer containing the bytes to write.
511 * @param count Maximum number of bytes to write.
513 * @return The number of bytes written, SP_ERR_FAIL on failure,
514 * or SP_ERR_ARG for invalid arguments.
516 enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
519 * Flush serial port buffers. Data in the selected buffer(s) is discarded.
521 * @param buffers Which buffer(s) to flush.
523 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
524 * if an invalid port is passed.
526 enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
530 * @defgroup Errors Obtaining error information
535 * Get the error code for a failed operation.
537 * In order to obtain the correct result, this function should be called
538 * straight after the failure, before executing any other system operations.
540 * @return The system's numeric code for the error that caused the last
543 int sp_last_error_code(void);
546 * Get the error message for a failed operation.
548 * In order to obtain the correct result, this function should be called
549 * straight after the failure, before executing other system operations.
551 * @return The system's message for the error that caused the last
552 * operation to fail. This string may be allocated by the function,
553 * and should be freed after use by calling sp_free_error_message().
555 char *sp_last_error_message(void);
558 * Free an error message returned by sp_last_error_message().
560 void sp_free_error_message(char *message);
568 #endif /* LIBSERIALPORT_H */