cfsetospeed - Man Page

set output baud rate


This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.


#include <termios.h>

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


The cfsetospeed() function shall set the output baud rate stored in the structure pointed to by termios_p to speed.

There shall be no effect on the baud rates set in the hardware until a subsequent successful call to tcsetattr() with the same termios structure. Similarly, errors resulting from attempts to set baud rates not supported by the terminal device need not be detected until the tcsetattr() function is called.

Return Value

Upon successful completion, cfsetospeed() shall return 0; otherwise, it shall return -1 and errno may be set to indicate the error.


The cfsetospeed() function may fail if:


The speed value is not a valid baud rate.


The value of speed is outside the range of possible speed values as specified in <termios.h>.

The following sections are informative.



Application Usage



Refer to cfgetispeed().

Future Directions


See Also

cfgetispeed(), cfgetospeed(), cfsetispeed(), tcsetattr()

The Base Definitions volume of POSIX.1-2017, Chapter 11, General Terminal Interface, <termios.h>

Referenced By

cfgetispeed(3p), cfgetospeed(3p), cfsetispeed(3p), termios.h(0p).

2017 IEEE/The Open Group POSIX Programmer's Manual