tcsendbreak - send a "break" for a specific duration
#include <termios.h>
int tcsendbreak(int fildes, int duration);
The fildes argument is an open file descriptor associated with a terminal.If the terminal is using asynchronous serial data transmission, tcsendbreak() will cause transmission of a continuous stream of zero-valued bits for a specific duration. If duration is 0, it will cause transmission of zero-valued bits for at least 0.25 seconds, and not more than 0.5 seconds. If duration is not 0, it will send zero-valued bits for an implementation-dependent period of time.
If the terminal is not using asynchronous serial data transmission, it is implementation-dependent whether tcsendbreak() sends data to generate a break condition or returns without taking any action.
Attempts to use tcsendbreak() from a process which is a member of a background process group on a fildes associated with its controlling terminal, will cause the process group to be sent a SIGTTOU signal. If the calling process is blocking or ignoring SIGTTOU signals, the process is allowed to perform the operation, and no signal is sent.
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.
The tcsendbreak() function will fail if:
- [EBADF]
The fildes argument is not a valid file descriptor.
- [ENOTTY]
The file associated with fildes is not a terminal.
The tcsendbreak() function may fail if:
- [EIO]
The process group of the writing process is orphaned, and the writing process is not ignoring or blocking SIGTTOU.
None.
None.
In the ISO POSIX-1 standard, the possibility of an [EIO] error occurring is described in XBD specification, Terminal Access Control, but it is not mentioned in the tcsendbreak() interface definition. It has become clear that this omission was unintended, so it is likely that the [EIO] error will be reclassified as a "will fail" in a future issue of the POSIX standard.
<termios.h>, <unistd.h>, the XBD specification, General Terminal Interface.