TCGETS, TCSETS, TCSETSW, TCSETSF, TCGETS2, TCSETS2, TCSETSW2, TCSETSF2, TCGETA, TCSETA, TCSETAW, TCSETAF

structtermios from <asm/termbits.h> is different and incompatible with structtermios from <termios.h>. These ioctl calls require structtermios from <asm/termbits.h>.

TCGETS Equivalent to tcgetattr(fd,argp). Get the current serial port settings. TCSETS Equivalent to tcsetattr(fd,TCSANOW,argp). Set the current serial port settings. TCSETSW Equivalent to tcsetattr(fd,TCSADRAIN,argp). Allow the output buffer to drain, and set the current serial port settings. TCSETSF Equivalent to tcsetattr(fd,TCSAFLUSH,argp). Allow the output buffer to drain, discard pending input, and set the current serial port settings. The following four ioctls are just like TCGETS, TCSETS, TCSETSW, TCSETSF, except that they take a structtermios2* instead of a structtermios*. If the structure member c_cflag contains the flag BOTHER, then the baud rate is stored in the structure members c_ispeed and c_ospeed as integer values. These ioctls are not supported on all architectures. TCGETS2TCSETS2TCSETSW2TCSETSF2 The following four ioctls are just like TCGETS, TCSETS, TCSETSW, TCSETSF, except that they take a structtermio* instead of a structtermios*. TCGETATCSETATCSETAWTCSETAF

EPERM Insufficient permission.

Get or set arbitrary baudrate on the serial port. /* SPDX-License-Identifier: GPL-2.0-or-later */ #include <asm/termbits.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <sys/ioctl.h> #include <unistd.h> int main(int argc, char *argv[]) { #if !defined BOTHER fprintf(stderr, "BOTHER is unsupported\n"); /* Program may fallback to TCGETS/TCSETS with Bnnn constants */ exit(EXIT_FAILURE); #else /* Declare tio structure, its type depends on supported ioctl */ # if defined TCGETS2 struct termios2 tio; # else struct termios tio; # endif int fd, rc; if (argc != 2 && argc != 3 && argc != 4) { fprintf(stderr, "Usage: %s device [output [input] ]\n", argv[0]); exit(EXIT_FAILURE); } fd = open(argv[1], O_RDWR | O_NONBLOCK | O_NOCTTY); if (fd < 0) { perror("open"); exit(EXIT_FAILURE); } /* Get the current serial port settings via supported ioctl */ # if defined TCGETS2 rc = ioctl(fd, TCGETS2, &tio); # else rc = ioctl(fd, TCGETS, &tio); # endif if (rc) { perror("TCGETS"); close(fd); exit(EXIT_FAILURE); } /* Change baud rate when more arguments were provided */ if (argc == 3 || argc == 4) { /* Clear the current output baud rate and fill a new value */ tio.c_cflag &= ~CBAUD; tio.c_cflag |= BOTHER; tio.c_ospeed = atoi(argv[2]); /* Clear the current input baud rate and fill a new value */ tio.c_cflag &= ~(CBAUD << IBSHIFT); tio.c_cflag |= BOTHER << IBSHIFT; /* When 4th argument is not provided reuse output baud rate */ tio.c_ispeed = (argc == 4) ? atoi(argv[3]) : atoi(argv[2]); /* Set new serial port settings via supported ioctl */ # if defined TCSETS2 rc = ioctl(fd, TCSETS2, &tio); # else rc = ioctl(fd, TCSETS, &tio); # endif if (rc) { perror("TCSETS"); close(fd); exit(EXIT_FAILURE); } /* And get new values which were really configured */ # if defined TCGETS2 rc = ioctl(fd, TCGETS2, &tio); # else rc = ioctl(fd, TCGETS, &tio); # endif if (rc) { perror("TCGETS"); close(fd); exit(EXIT_FAILURE); } } close(fd); printf("output baud rate: %u\n", tio.c_ospeed); printf("input baud rate: %u\n", tio.c_ispeed); exit(EXIT_SUCCESS); #endif }

TCGETS2TCSETS2TCSETSW2TCSETSF2 Linux 2.6.20.

Standard C library (libc, -lc)

TCGETS, TCSETS, TCSETSW, TCSETSF, TCGETS2, TCSETS2, TCSETSW2, TCSETSF2, TCGETA, TCSETA, TCSETAW, TCSETAF - get and set terminal attributes

On success, 0 is returned. On error, -1 is returned and errno is set to indicate the error.

ioctl(2), ioctl_tty(2), termios(3) Linux man-pages 6.9.1 2024-06-15 TCSETS(2const)

#include<asm/termbits.h> /* Definition of TC* constants */ #include<sys/ioctl.h>intioctl(intfd,TCGETS,structtermios*argp);intioctl(intfd,TCSETS,conststructtermios*argp);intioctl(intfd,TCSETSW,conststructtermios*argp);intioctl(intfd,TCSETSF,conststructtermios*argp);intioctl(intfd,TCGETS2,structtermios2*argp);intioctl(intfd,TCSETS2,conststructtermios2*argp);intioctl(intfd,TCSETSW2,conststructtermios2*argp);intioctl(intfd,TCSETSF2,conststructtermios2*argp);intioctl(intfd,TCGETA,structtermio*argp);intioctl(intfd,TCSETA,conststructtermio*argp);intioctl(intfd,TCSETAW,conststructtermio*argp);intioctl(intfd,TCSETAF,conststructtermio*argp);#include<asm/termbits.h>structtermios;structtermios2;structtermio;