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.
cfsetispeed — set input baud rate
int cfsetispeed(struct termios *termios_p, speed_t speed);
The cfsetispeed() function shall set the input 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.
Upon successful completion, cfsetispeed() shall return 0; otherwise,
−1 shall be returned, and errno may be set to indicate the
The cfsetispeed() 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.
The Base Definitions volume of POSIX.1‐2008, Chapter
11, General Terminal Interface,
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
7, Copyright (C) 2013 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013
Technical Corrigendum 1 applied.) In the event of any discrepancy between this
version and the original IEEE and The Open Group Standard, the original IEEE
and The Open Group Standard is the referee document. The original Standard can
be obtained online at http://www.unix.org/online.html .
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