1TCFLOW(3P) POSIX Programmer's Manual TCFLOW(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 tcflow — suspend or restart the transmission or reception of data
13
15 #include <termios.h>
16 int tcflow(int fildes, int action);
18
20 The tcflow() function shall suspend or restart transmission or recep‐
21 tion of data on the object referred to by fildes, depending on the
22 value of action. The fildes argument is an open file descriptor asso‐
23 ciated with a terminal.
24 * If action is TCOOFF, output shall be suspended.
26 * If action is TCOON, suspended output shall be restarted.
28 * If action is TCIOFF and fildes refers to a terminal device, the
30 system shall transmit a STOP character, which is intended to cause
31 the terminal device to stop transmitting data to the system. If
32 fildes is associated with a pseudo-terminal, the STOP character
33 need not be transmitted.
34 * If action is TCION and fildes refers to a terminal device, the sys‐
36 tem shall transmit a START character, which is intended to cause
37 the terminal device to start transmitting data to the system. If
38 fildes is associated with a pseudo-terminal, the START character
39 need not be transmitted.
40 The default on the opening of a terminal file is that neither its input
42 nor its output are suspended.
43 Attempts to use tcflow() from a process which is a member of a back‐
45 ground process group on a fildes associated with its controlling termi‐
46 nal, shall cause the process group to be sent a SIGTTOU signal. If the
47 calling thread is blocking SIGTTOU signals or the process is ignoring
48 SIGTTOU signals, the process shall be allowed to perform the operation,
49 and no signal is sent.
50
52 Upon successful completion, 0 shall be returned. Otherwise, -1 shall be
53 returned and errno set to indicate the error.
54
56 The tcflow() function shall fail if:
57 EBADF The fildes argument is not a valid file descriptor.
59 EINVAL The action argument is not a supported value.
61 EIO The process group of the writing process is orphaned, the call‐
63 ing thread is not blocking SIGTTOU, and the process is not
64 ignoring SIGTTOU.
65 ENOTTY The file associated with fildes is not a terminal.
67 The following sections are informative.
69
71 None.
72
74 None.
75
77 None.
78
80 None.
81
83 tcsendbreak()
84 The Base Definitions volume of POSIX.1‐2017, Chapter 11, General Termi‐
86 nal Interface, <termios.h>
87
89 Portions of this text are reprinted and reproduced in electronic form
90 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
91 table Operating System Interface (POSIX), The Open Group Base Specifi‐
92 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
93 Electrical and Electronics Engineers, Inc and The Open Group. In the
94 event of any discrepancy between this version and the original IEEE and
95 The Open Group Standard, the original IEEE and The Open Group Standard
96 is the referee document. The original Standard can be obtained online
97 at http://www.opengroup.org/unix/online.html .
98 Any typographical or formatting errors that appear in this page are
100 most likely to have been introduced during the conversion of the source
101 files to man page format. To report such errors, see https://www.ker‐
102 nel.org/doc/man-pages/reporting_bugs.html .
103IEEE/The Open Group 2017 TCFLOW(3P)