summaryrefslogtreecommitdiffstats
path: root/lib/libc/gen/tcsetattr.3
blob: d3b2b4f55bfe2f0c0ef7e8ab2fedab5c134ba708 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)tcsetattr.3	8.3 (Berkeley) 1/2/94
.\"
.Dd "January 2, 1994"
.Dt TCSETATTR 3
.Os
.Sh NAME
.Nm cfgetispeed ,
.Nm cfsetispeed ,
.Nm cfgetospeed ,
.Nm cfsetospeed ,
.Nm cfsetspeed ,
.Nm cfmakeraw ,
.Nm tcgetattr ,
.Nm tcsetattr
.Nd manipulating the termios structure
.Sh SYNOPSIS
.Fd #include <termios.h>
.Ft speed_t
.Fn cfgetispeed "struct termios *t"
.Ft int
.Fn cfsetispeed "struct termios *t" "speed_t speed"
.Ft speed_t
.Fn cfgetospeed "struct termios *t"
.Ft int
.Fn cfsetospeed "struct termios *t" "speed_t speed"
.Ft int
.Fn cfsetspeed "struct termios *t" "speed_t speed"
.Ft void
.Fn cfmakeraw "struct termios *t"
.Ft int
.Fn tcgetattr "int fd" "struct termios *t"
.Ft int
.Fn tcsetattr "int fd" "int action" "struct termios *t"
.Sh DESCRIPTION
The
.Nm cfmakeraw ,
.Nm tcgetattr
and
.Nm tcsetattr
functions are provided for getting and setting the termios structure.
.Pp
The
.Nm cfgetispeed ,
.Nm cfsetispeed ,
.Nm cfgetospeed ,
.Nm cfsetospeed
and
.Nm cfsetspeed
functions are provided for getting and setting the baud rate values in
the termios structure.
The effects of the functions on the terminal as described below
do not become effective, nor are all errors detected, until the
.Nm tcsetattr
function is called.
Certain values for baud rates set in the termios structure and passed to
.Nm tcsetattr
have special meanings.
These are discussed in the portion of the manual page that describes the
.Nm tcsetattr
function.
.Sh GETTING AND SETTING THE BAUD RATE
The input and output baud rates are found in the termios structure.
The unsigned integer
.Li speed_t
is typdef'd in the include file
.Aq Pa termios.h .
The value of the integer corresponds directly to the baud rate being
represented, however, the following symbolic values are defined.
.Bd -literal
#define B0	0
#define B50	50
#define B75	75
#define B110	110
#define B134	134
#define B150	150
#define B200	200
#define B300	300
#define B600	600
#define B1200	1200
#define	B1800	1800
#define B2400	2400
#define B4800	4800
#define B9600	9600
#define B19200	19200
#define B38400	38400
#ifndef _POSIX_SOURCE
#define EXTA	19200
#define EXTB	38400
#endif  /*_POSIX_SOURCE */
.Ed
.Pp
The
.Nm cfgetispeed
function returns the input baud rate in the termios structure referenced by
.Fa tp .
.Pp
The
.Nm cfsetispeed
function sets the input baud rate in the termios structure referenced by
.Fa tp
to
.Fa speed .
.Pp
The
.Nm cfgetospeed
function returns the output baud rate in the termios structure referenced by
.Fa tp .
.Pp
The
.Nm cfsetospeed
function sets the output baud rate in the termios structure referenced by
.Fa tp
to
.Fa speed .
.Pp
The
.Nm cfsetspeed
function sets both the input and output baud rate in the termios structure
referenced by
.Fa tp
to
.Fa speed .
.Pp
Upon successful completion, the functions
.Nm cfsetispeed ,
.Nm cfsetospeed ,
and
.Nm cfsetspeed
return a value of 0.
Otherwise, a value of -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh GETTING AND SETTING THE TERMIOS STATE
This section describes the functions that are used to control the general
terminal interface.
Unless otherwise noted for a specific command, these functions are restricted
from use by background processes.
Attempts to perform these operations shall cause the process group to be sent
a SIGTTOU signal.
If the calling process is blocking or ignoring SIGTTOU signals, the process
is allowed to perform the operation and the SIGTTOU signal is not sent.
.Pp
In all the functions, although
.Fa fd
is an open file descriptor, the functions affect the underlying terminal
file, not just the open file description associated with the particular
file descriptor.
.Pp
The
.Nm cfmakeraw
function sets the flags stored in the termios structure to a state disabling
all input and output processing, giving a
.Dq raw I/O path.
It should be noted that there is no function to reverse this effect.
This is because there are a variety of processing options that could be
re-enabled and the correct method is for an application to snapshot the
current terminal state using the function
.Nm tcgetattr ,
setting raw mode with
.Nm cfmakeraw
and the subsequent
.Nm tcsetattr ,
and then using another
.Nm tcsetattr
with the saved state to revert to the previous terminal state.
.Pp
The
.Nm tcgetattr
function copies the parameters associated with the terminal referenced
by
.Fa fd
in the termios structure referenced by
.Fa tp .
This function is allowed from a background process, however, the terminal
attributes may be subsequently changed by a foreground process.
.Pp
The
.Nm tcsetattr
function sets the parameters associated with the terminal from the
termios structure referenced by
.Fa tp .
The
.Fa action
field is created by
.Em or Ns 'ing
the following values, as specified in the include file
.Aq Pa termios.h .
.Bl -tag -width "TCSADRAIN"
.It Fa TCSANOW
The change occurs immediately.
.It Fa TCSADRAIN
The change occurs after all output written to
.Fa fd
has been transmitted to the terminal.
This value of
.Fa action
should be used when changing parameters that affect output.
.It Fa TCSAFLUSH
The change occurs after all output written to
.Fa fd
has been transmitted to the terminal.
Additionally, any input that has been received but not read is discarded.
.It Fa TCSASOFT
If this value is
.Em or Ns 'ed
into the
.Fa action
value, the values of the
.Em c_cflag ,
.Em c_ispeed ,
and
.Em c_ospeed
fields are ignored.
.El
.Pp
The 0 baud rate is used to terminate the connection.
If 0 is specified as the output speed to the function
.Nm tcsetattr ,
modem control will no longer be asserted on the terminal, disconnecting
the terminal.
.Pp
If zero is specified as the input speed to the function
.Nm tcsetattr ,
the input baud rate will be set to the same value as that specified by
the output baud rate.
.Pp
If
.Nm tcsetattr
is unable to make any of the requested changes, it returns -1 and
sets errno.
Otherwise, it makes all of the requested changes it can.
If the specified input and output baud rates differ and are a combination
that is not supported, neither baud rate is changed.
.Pp
Upon successful completion, the functions
.Nm tcgetattr
and
.Nm tcsetattr
return a value of 0.
Otherwise, they
return -1 and the global variable
.Va errno
is set to indicate the error, as follows:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa fd
argument to
.Nm tcgetattr
or
.Nm tcsetattr
was not a valid file descriptor.
.It Bq Er EINTR
The
.Nm tcsetattr
function was interrupted by a signal.
.It Bq Er EINVAL
The
.Fa action
argument to the
.Nm tcsetattr
function was not valid, or an attempt was made to change an attribute
represented in the termios structure to an unsupported value.
.It Bq Er ENOTTY
The file associated with the
.Fa fd
argument to
.Nm tcgetattr
or
.Nm tcsetattr
is not a terminal.
.El
.Sh SEE ALSO
.Xr tcsendbreak 3 ,
.Xr termios 4
.Sh STANDARDS
The
.Nm cfgetispeed ,
.Nm cfsetispeed ,
.Nm cfgetospeed ,
.Nm cfsetospeed ,
.Nm tcgetattr
and
.Nm tcsetattr
functions are expected to be compliant with the
.St -p1003.1-88
specification.
The
.Nm cfmakeraw
and
.Nm cfsetspeed
functions,
as well as the
.Li TCSASOFT
option to the
.Nm tcsetattr
function are extensions to the
.St -p1003.1-88
specification.
OpenPOWER on IntegriCloud