tcflow(3) Library Functions Manual tcflow(3)

tcflow - suspect transmission or reception of data

Standard C library (libc, -lc)

#include <termios.h>
int tcflow(int fd, int action);

tcflow() suspends transmission or reception of data on the object referred to by fd, depending on the value of action:

suspends output.
restarts suspended output.
transmits a STOP character, which stops the terminal device from transmitting data to the system.
transmits a START character, which starts the terminal device transmitting data to the system.

The default on open of a terminal file is that neither its input nor its output is suspended.

0
on success.
-1
on failure and set errno to indicate the error.

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
tcflow () Thread safety MT-Safe

POSIX.1-2008.

POSIX.1-2001.

tcsendbreak(3), tcdrain(3), tcflush(3), termios(7)

2026-07-02 Linux man-pages 6.19