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glibc/sysdeps/unix/sysv/linux/speed.c
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/* `struct termios' speed frobnication functions. Linux version. | |
Copyright (C) 1991-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <stddef.h> | |
#include <errno.h> | |
#include <termios.h> | |
/* This is a gross hack around a kernel bug. If the cfsetispeed functions | |
is called with the SPEED argument set to zero this means use the same | |
speed as for output. But we don't have independent input and output | |
speeds and therefore cannot record this. | |
We use an unused bit in the `c_iflag' field to keep track of this | |
use of `cfsetispeed'. The value here must correspond to the one used | |
in `tcsetattr.c'. */ | |
#define IBAUD0 020000000000 | |
/* Return the output baud rate stored in *TERMIOS_P. */ | |
speed_t | |
cfgetospeed (const struct termios *termios_p) | |
{ | |
return termios_p->c_cflag & (CBAUD | CBAUDEX); | |
} | |
/* Return the input baud rate stored in *TERMIOS_P. | |
Although for Linux there is no difference between input and output | |
speed, the numerical 0 is a special case for the input baud rate. It | |
should set the input baud rate to the output baud rate. */ | |
speed_t | |
cfgetispeed (const struct termios *termios_p) | |
{ | |
return ((termios_p->c_iflag & IBAUD0) | |
? 0 : termios_p->c_cflag & (CBAUD | CBAUDEX)); | |
} | |
/* Set the output baud rate stored in *TERMIOS_P to SPEED. */ | |
int | |
cfsetospeed (struct termios *termios_p, speed_t speed) | |
{ | |
if ((speed & ~CBAUD) != 0 | |
&& (speed < B57600 || speed > __MAX_BAUD)) | |
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); | |
#ifdef _HAVE_STRUCT_TERMIOS_C_OSPEED | |
termios_p->c_ospeed = speed; | |
#endif | |
termios_p->c_cflag &= ~(CBAUD | CBAUDEX); | |
termios_p->c_cflag |= speed; | |
return 0; | |
} | |
libc_hidden_def (cfsetospeed) | |
/* Set the input baud rate stored in *TERMIOS_P to SPEED. | |
Although for Linux there is no difference between input and output | |
speed, the numerical 0 is a special case for the input baud rate. It | |
should set the input baud rate to the output baud rate. */ | |
int | |
cfsetispeed (struct termios *termios_p, speed_t speed) | |
{ | |
if ((speed & ~CBAUD) != 0 | |
&& (speed < B57600 || speed > __MAX_BAUD)) | |
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); | |
#ifdef _HAVE_STRUCT_TERMIOS_C_ISPEED | |
termios_p->c_ispeed = speed; | |
#endif | |
if (speed == 0) | |
termios_p->c_iflag |= IBAUD0; | |
else | |
{ | |
termios_p->c_iflag &= ~IBAUD0; | |
termios_p->c_cflag &= ~(CBAUD | CBAUDEX); | |
termios_p->c_cflag |= speed; | |
} | |
return 0; | |
} | |
libc_hidden_def (cfsetispeed) |