cfsetispeed()

Set the input baud rate in a termios structure

Synopsis:

#include <termios.h>

int cfsetispeed( struct termios* termios_p,
                 speed_t speed );

Arguments:

termios_p: A pointer to a termios structure that describes the terminal's control attributes.
speed: The new speed. Valid values for speed are defined in <termios.h>.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The cfsetispeed() function sets the input baud rate within the termios structure pointed to by termios_p to be speed.

You can get a valid termios control structure for an opened device by calling tcgetattr().

Note:

The new baud rate isn't effective until you call tcsetattr() with this modified termios structure.
Attempts to set baud rates to values that aren't supported by the hardware are ignored, and cause tcsetattr() to return an error, but cfsetispeed() doesn't indicate an error.
Attempts to set input baud rates to a value that's different from the output baud rate, when the hardware doesn't support split baud rates, cause the input baud rate to be ignored, but no error is generated.

Returns:

0: Success.
-1: An error occurred (errno is set).

Errors:

EINVAL: One of the arguments is invalid.
ENOTTY: This function isn't supported by the system.

Examples:

#include <termios.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

int main( void )
  {
    int fd;
    struct termios termios_p;
    speed_t speed;

    fd = open( "/dev/ser1", O_RDWR );
    tcgetattr( fd, &termios_p);

    /*
     *    Set input baud rate
     */
    speed = 9600;
    cfsetispeed( &termios_p, speed );
    tcsetattr( fd, TCSADRAIN, &termios_p);

    close( fd );
    return EXIT_SUCCESS;
  }

Classification:

POSIX 1003.1

Safety:
Cancellation point	No
Interrupt handler	Yes
Signal handler	Yes
Thread	Yes