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.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html