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1 | /* | |
2 | * This file is part of the libserialport project. | |
3 | * | |
4 | * Copyright (C) 2013 Martin Ling <martin-libserialport@earth.li> | |
5 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
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/>. | |
18 | */ | |
19 | ||
20 | /** | |
21 | ||
22 | \mainpage libserialport API | |
23 | ||
24 | Introduction | |
25 | ============ | |
26 | ||
27 | libserialport is a minimal library written in C that is intended to take care | |
28 | of the OS-specific details when writing software that uses serial ports. | |
29 | ||
30 | By writing your serial code to use libserialport, you enable it to work | |
31 | transparently on any platform supported by the library. | |
32 | ||
33 | The operations that are supported are: | |
34 | ||
35 | - \ref Enumeration (obtaining a list of serial ports on the system). | |
36 | - \ref Ports | |
37 | - \ref Configuration (baud rate, parity, etc) | |
38 | - \ref Data | |
39 | - \ref Errors | |
40 | ||
41 | libserialport is an open source project released under the LGPL3+ license. | |
42 | ||
43 | API principles | |
44 | ============== | |
45 | ||
46 | The API is simple, and designed to be a minimal wrapper around the serial port | |
47 | support in each OS. | |
48 | ||
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. | |
52 | ||
53 | All functions can return only three possible error values. SP_ERR_ARG indicates | |
54 | the function was called with invalid arguments. SP_ERR_FAIL indicates that the | |
55 | OS reported a failure. SP_ERR_MEM indicates that a memory allocation failed. | |
56 | All of these error values are negative. | |
57 | ||
58 | When SP_ERR_FAIL is returned, an error code or string description of the error | |
59 | can be obtained by calling sp_last_error_code() or sp_last_error_message(). The | |
60 | error code or message is that provided by the OS; libserialport does not define | |
61 | any error codes or messages of its own. | |
62 | ||
63 | Function calls that succeed return SP_OK, which is equal to zero, or where | |
64 | otherwise documented a positive value. | |
65 | ||
66 | */ | |
67 | ||
68 | #ifndef LIBSERIALPORT_H | |
69 | #define LIBSERIALPORT_H | |
70 | ||
71 | #ifdef __cplusplus | |
72 | extern "C" { | |
73 | #endif | |
74 | ||
75 | #include <stddef.h> | |
76 | #ifdef _WIN32 | |
77 | #include <windows.h> | |
78 | #endif | |
79 | ||
80 | /* Package version macros (e.g. for conditional compilation). */ | |
81 | #define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@ | |
82 | #define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@ | |
83 | #define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@" | |
84 | ||
85 | /* Library/libtool version macros (e.g. for conditional compilation). */ | |
86 | #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@ | |
87 | #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@ | |
88 | #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@ | |
89 | #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@" | |
90 | ||
91 | /** Return values. */ | |
92 | enum sp_return { | |
93 | /** Operation completed successfully. */ | |
94 | SP_OK = 0, | |
95 | /** Invalid arguments were passed to the function. */ | |
96 | SP_ERR_ARG = -1, | |
97 | /** A system error occured while executing the operation. */ | |
98 | SP_ERR_FAIL = -2, | |
99 | /** A memory allocation failed while executing the operation. */ | |
100 | SP_ERR_MEM = -3, | |
101 | }; | |
102 | ||
103 | /** Port access modes. */ | |
104 | enum sp_mode { | |
105 | /** Open port for read/write access. */ | |
106 | SP_MODE_RDWR = 1, | |
107 | /** Open port for read access only. */ | |
108 | SP_MODE_RDONLY = 2, | |
109 | /** Open port in non-blocking mode. */ | |
110 | SP_MODE_NONBLOCK = 4, | |
111 | }; | |
112 | ||
113 | /** Parity settings. */ | |
114 | enum sp_parity { | |
115 | SP_PARITY_INVALID = -1, | |
116 | /** No parity. */ | |
117 | SP_PARITY_NONE = 0, | |
118 | /** Even parity. */ | |
119 | SP_PARITY_EVEN = 1, | |
120 | /** Odd parity. */ | |
121 | SP_PARITY_ODD = 2, | |
122 | }; | |
123 | ||
124 | /** RTS pin behaviour. */ | |
125 | enum sp_rts { | |
126 | SP_RTS_INVALID = -1, | |
127 | /** RTS off. */ | |
128 | SP_RTS_OFF = 0, | |
129 | /** RTS on. */ | |
130 | SP_RTS_ON = 1, | |
131 | /** RTS used for flow control. */ | |
132 | SP_RTS_FLOW_CONTROL = 2 | |
133 | }; | |
134 | ||
135 | /** CTS pin behaviour. */ | |
136 | enum sp_cts { | |
137 | SP_CTS_INVALID = -1, | |
138 | /** CTS ignored. */ | |
139 | SP_CTS_IGNORE = 0, | |
140 | /** CTS used for flow control. */ | |
141 | SP_CTS_FLOW_CONTROL = 1 | |
142 | }; | |
143 | ||
144 | /** DTR pin behaviour. */ | |
145 | enum sp_dtr { | |
146 | SP_DTR_INVALID = -1, | |
147 | /** DTR off. */ | |
148 | SP_DTR_OFF = 0, | |
149 | /** DTR on. */ | |
150 | SP_DTR_ON = 1, | |
151 | /** DTR used for flow control. */ | |
152 | SP_DTR_FLOW_CONTROL = 2 | |
153 | }; | |
154 | ||
155 | /** DSR pin behaviour. */ | |
156 | enum sp_dsr { | |
157 | SP_DSR_INVALID = -1, | |
158 | /** DSR ignored. */ | |
159 | SP_DSR_IGNORE = 0, | |
160 | /** DSR used for flow control. */ | |
161 | SP_DSR_FLOW_CONTROL = 1 | |
162 | }; | |
163 | ||
164 | /** XON/XOFF flow control behaviour. */ | |
165 | enum sp_xonxoff { | |
166 | SP_XONXOFF_INVALID = -1, | |
167 | /** XON/XOFF disabled. */ | |
168 | SP_XONXOFF_DISABLED = 0, | |
169 | /** XON/XOFF enabled for input only. */ | |
170 | SP_XONXOFF_IN = 1, | |
171 | /** XON/XOFF enabled for output only. */ | |
172 | SP_XONXOFF_OUT = 2, | |
173 | /** XON/XOFF enabled for input and output. */ | |
174 | SP_XONXOFF_INOUT = 3 | |
175 | }; | |
176 | ||
177 | /** Standard flow control combinations. */ | |
178 | enum sp_flowcontrol { | |
179 | /** No flow control. */ | |
180 | SP_FLOWCONTROL_NONE = 0, | |
181 | /** Software flow control using XON/XOFF characters. */ | |
182 | SP_FLOWCONTROL_XONXOFF = 1, | |
183 | /** Hardware flow control using RTS/CTS signals. */ | |
184 | SP_FLOWCONTROL_RTSCTS = 2, | |
185 | /** Hardware flow control using DTR/DSR signals. */ | |
186 | SP_FLOWCONTROL_DTRDSR = 3 | |
187 | }; | |
188 | ||
189 | /** A serial port. */ | |
190 | struct sp_port { | |
191 | /** Name used to open the port */ | |
192 | char *name; | |
193 | /** \cond 0 */ | |
194 | /* OS-specific port handle */ | |
195 | #ifdef _WIN32 | |
196 | HANDLE hdl; | |
197 | #else | |
198 | int fd; | |
199 | #endif | |
200 | /** \endcond */ | |
201 | }; | |
202 | ||
203 | /** Configuration for a serial port. */ | |
204 | struct sp_port_config { | |
205 | /** Baud rate in bits per second. */ | |
206 | int baudrate; | |
207 | /** Number of data bits to use. Valid values are 5 to 8. */ | |
208 | int bits; | |
209 | /** Parity setting to use. */ | |
210 | enum sp_parity parity; | |
211 | /** Number of stop bits to use (1 or 2). */ | |
212 | int stopbits; | |
213 | /** RTS pin mode. */ | |
214 | enum sp_rts rts; | |
215 | /** CTS pin mode. */ | |
216 | enum sp_cts cts; | |
217 | /** DTR pin mode. */ | |
218 | enum sp_dtr dtr; | |
219 | /** DSR pin mode. */ | |
220 | enum sp_dsr dsr; | |
221 | /** XON/XOFF flow control mode. */ | |
222 | enum sp_xonxoff xon_xoff; | |
223 | }; | |
224 | ||
225 | /** | |
226 | \defgroup Enumeration Port enumeration | |
227 | @{ | |
228 | */ | |
229 | ||
230 | /** | |
231 | Obtains a pointer to a new sp_port structure representing the named port. The | |
232 | user should allocate a variable of type "struct sp_port *" and pass a pointer | |
233 | to this to receive the result. | |
234 | ||
235 | The result should be freed after use by calling sp_free_port(). | |
236 | ||
237 | @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation | |
238 | failure, or SP_ERR_ARG if an invalid pointer is passed. If any error | |
239 | is returned, the variable pointed to by port_ptr will be set to NULL. | |
240 | Otherwise, it will be set to point to the newly allocated port. | |
241 | */ | |
242 | enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr); | |
243 | ||
244 | /** | |
245 | Frees a port structure obtained from sp_get_port_by_name() or sp_copy_port(). | |
246 | */ | |
247 | void sp_free_port(struct sp_port *port); | |
248 | ||
249 | /** | |
250 | Lists the serial ports available on the system. The result obtained is an | |
251 | array of pointers to sp_port structures, terminated by a NULL. The user should | |
252 | allocate a variable of type "struct sp_port **" and pass a pointer to this to | |
253 | receive the result. | |
254 | ||
255 | The result should be freed after use by calling sp_free_port_list(). If a port | |
256 | from the list is to be used after freeing the list, it must be copied first | |
257 | using sp_copy_port(). | |
258 | ||
259 | @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation | |
260 | failure, or SP_ERR_ARG if an invalid pointer is passed. If any error | |
261 | is returned, the variable pointed to by list_ptr will be set to NULL. | |
262 | Otherwise, it will be set to point to the newly allocated array. | |
263 | */ | |
264 | enum sp_return sp_list_ports(struct sp_port ***list_ptr); | |
265 | ||
266 | /** | |
267 | Makes a new copy of a sp_port structure. The user should allocate a variable | |
268 | of type "struct sp_port *" and pass a pointer to this to receive the result. | |
269 | ||
270 | The copy should be freed after use by calling sp_free_port(). | |
271 | ||
272 | @return SP_OK on success, SP_ERR_MEM on allocation failure, or SP_ERR_ARG | |
273 | if an invalid port or pointer is passed. If any error is returned, | |
274 | the variable pointed to by copy_ptr will be set to NULL. Otherwise, | |
275 | it will be set to point to the newly allocated copy. | |
276 | */ | |
277 | enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr); | |
278 | ||
279 | /** | |
280 | Frees a port list obtained from sp_list_ports(). This will also free all | |
281 | the sp_port structures referred to from the list; any that are to be retained | |
282 | must be copied first using sp_copy_port(). | |
283 | */ | |
284 | void sp_free_port_list(struct sp_port **ports); | |
285 | ||
286 | /** | |
287 | @} | |
288 | \defgroup Ports Opening & closing ports | |
289 | @{ | |
290 | */ | |
291 | ||
292 | /** | |
293 | Opens the specified serial port. | |
294 | ||
295 | @param port Pointer to port structure. | |
296 | @param flags Flags to use when opening the serial port. | |
297 | ||
298 | @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation | |
299 | failure, or SP_ERR_ARG if an invalid port is passed. | |
300 | */ | |
301 | enum sp_return sp_open(struct sp_port *port, enum sp_mode flags); | |
302 | ||
303 | /** | |
304 | Closes the specified serial port. | |
305 | ||
306 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
307 | if an invalid port is passed. | |
308 | */ | |
309 | enum sp_return sp_close(struct sp_port *port); | |
310 | ||
311 | /** | |
312 | @} | |
313 | \defgroup Configuration Setting port parameters | |
314 | @{ | |
315 | */ | |
316 | ||
317 | /** | |
318 | Gets current configuration of the specified serial port. | |
319 | ||
320 | The user should allocate a struct sp_port_config, then pass a pointer to it | |
321 | as the config parameter. The struct will be populated with the port | |
322 | configuration. | |
323 | ||
324 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
325 | for invalid arguments. | |
326 | */ | |
327 | enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config); | |
328 | ||
329 | /** | |
330 | Sets all parameters for the specified serial port. | |
331 | ||
332 | The user should populate a struct sp_port_config, then pass a pointer to it | |
333 | as the config parameter. | |
334 | ||
335 | To retain the current value of any setting, set the field to to a | |
336 | negative value. | |
337 | ||
338 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
339 | for invalid arguments. | |
340 | */ | |
341 | enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config); | |
342 | ||
343 | /** | |
344 | Sets the baud rate for the specified serial port. | |
345 | ||
346 | @param port Pointer to port structure. | |
347 | @param baud Baud rate in bits per second. | |
348 | ||
349 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
350 | for invalid arguments. | |
351 | */ | |
352 | enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate); | |
353 | ||
354 | /** | |
355 | Sets the number of data bits for the specified serial port. | |
356 | ||
357 | @param port Pointer to port structure. | |
358 | @param bits Number of data bits to use. Valid values are 5 to 8. | |
359 | ||
360 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
361 | for invalid arguments. | |
362 | */ | |
363 | enum sp_return sp_set_bits(struct sp_port *port, int bits); | |
364 | ||
365 | /** | |
366 | Sets the parity for the specified serial port. | |
367 | ||
368 | @param port Pointer to port structure. | |
369 | @param parity Parity setting to use. | |
370 | ||
371 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
372 | for invalid arguments. | |
373 | */ | |
374 | enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity); | |
375 | ||
376 | /** | |
377 | Sets the number of stop bits for the specified port. | |
378 | ||
379 | @param port Pointer to port structure. | |
380 | @param stopbits Number of stop bits to use (1 or 2). | |
381 | ||
382 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
383 | for invalid arguments. | |
384 | */ | |
385 | enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits); | |
386 | ||
387 | /** | |
388 | Sets the flow control type for the specified serial port. | |
389 | ||
390 | This function is a wrapper that sets the RTS, CTS, DTR, DSR and | |
391 | XON/XOFF settings as necessary for the specified flow control | |
392 | type. For more fine-grained control of these settings, use their | |
393 | individual configuration functions or the sp_set_config() function. | |
394 | ||
395 | @param port Pointer to port structure. | |
396 | @param flowcontrol Flow control setting to use. | |
397 | ||
398 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
399 | for invalid arguments. | |
400 | */ | |
401 | enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol); | |
402 | ||
403 | /** | |
404 | Sets the RTS pin behaviour for the specified port. | |
405 | ||
406 | @param port Pointer to port structure. | |
407 | @param rts RTS pin mode. | |
408 | ||
409 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
410 | for invalid arguments. | |
411 | */ | |
412 | enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts); | |
413 | ||
414 | /** | |
415 | Sets the CTS pin behaviour for the specified port. | |
416 | ||
417 | @param port Pointer to port structure. | |
418 | @param cts CTS pin mode. | |
419 | ||
420 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
421 | for invalid arguments. | |
422 | */ | |
423 | enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts); | |
424 | ||
425 | /** | |
426 | Sets the DTR pin behaviour for the specified port. | |
427 | ||
428 | @param port Pointer to port structure. | |
429 | @param dtr DTR pin mode. | |
430 | ||
431 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
432 | for invalid arguments. | |
433 | */ | |
434 | enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr); | |
435 | ||
436 | /** | |
437 | Sets the RTS pin behaviour for the specified port. | |
438 | ||
439 | @param port Pointer to port structure. | |
440 | @param dsr DSR pin mode. | |
441 | ||
442 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
443 | for invalid arguments. | |
444 | */ | |
445 | enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr); | |
446 | ||
447 | /** | |
448 | Configures XON/XOFF flow control for the specified port. | |
449 | ||
450 | @param port Pointer to port structure. | |
451 | @param xon_xoff XON/XOFF flow control mode. | |
452 | ||
453 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
454 | for invalid arguments. | |
455 | */ | |
456 | enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff); | |
457 | ||
458 | /** | |
459 | @} | |
460 | \defgroup Data Reading, writing & flushing data | |
461 | @{ | |
462 | */ | |
463 | ||
464 | /** | |
465 | Reads bytes from the specified serial port. Note that this function may | |
466 | return after reading less than the specified number of bytes; it is the | |
467 | user's responsibility to iterate as necessary in this case. | |
468 | ||
469 | @param port Pointer to port structure. | |
470 | @param buf Buffer in which to store the bytes read. | |
471 | @param count Maximum number of bytes to read. | |
472 | ||
473 | @return The number of bytes read, SP_ERR_FAIL on failure, | |
474 | or SP_ERR_ARG for invalid arguments. | |
475 | */ | |
476 | enum sp_return sp_read(struct sp_port *port, void *buf, size_t count); | |
477 | ||
478 | /** | |
479 | Write bytes to the specified serial port. Note that this function may | |
480 | return after writing less than the specified number of bytes; it is the | |
481 | user's responsibility to iterate as necessary in this case. | |
482 | ||
483 | @param port Pointer to port structure. | |
484 | @param buf Buffer containing the bytes to write. | |
485 | @param count Maximum number of bytes to write. | |
486 | ||
487 | @return The number of bytes written, SP_ERR_FAIL on failure, | |
488 | or SP_ERR_ARG for invalid arguments. | |
489 | */ | |
490 | enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count); | |
491 | ||
492 | /** | |
493 | Flushes serial port buffers. | |
494 | ||
495 | @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG | |
496 | if an invalid port is passed. | |
497 | */ | |
498 | enum sp_return sp_flush(struct sp_port *port); | |
499 | ||
500 | /** | |
501 | @} | |
502 | \defgroup Errors Obtaining error information | |
503 | @{ | |
504 | */ | |
505 | ||
506 | /** | |
507 | Gets the error code for a failed operation. | |
508 | ||
509 | In order to obtain the correct result, this function should be called | |
510 | straight after the failure, before executing any other system operations. | |
511 | ||
512 | @return The system's numeric code for the error that caused the last | |
513 | operation to fail. | |
514 | */ | |
515 | int sp_last_error_code(void); | |
516 | ||
517 | /** | |
518 | Gets the error message for a failed operation. | |
519 | ||
520 | In order to obtain the correct result, this function should be called | |
521 | straight after the failure, before executing other system operations. | |
522 | ||
523 | @return The system's message for the error that caused the last | |
524 | operation to fail. This string may be allocated by the function, | |
525 | and should be freed after use by calling sp_free_error_message. | |
526 | */ | |
527 | char *sp_last_error_message(void); | |
528 | ||
529 | /** | |
530 | Frees an error message returned by sp_last_error_message(). | |
531 | */ | |
532 | void sp_free_error_message(char *message); | |
533 | ||
534 | /** | |
535 | @} | |
536 | */ | |
537 | ||
538 | #ifdef __cplusplus | |
539 | } | |
540 | #endif | |
541 | ||
542 | #endif /* LIBSERIALPORT_H */ | |
543 |