View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001932 | 1003.1(2024)/Issue8 | Base Definitions and Headers | public | 2025-06-24 23:46 | 2025-08-05 11:09 |
| Reporter | hpa | Assigned To | geoffclare | ||
| Priority | normal | Severity | Editorial | Type | Clarification Requested |
| Status | Applied | Resolution | Accepted As Marked | ||
| Name | H. Peter Anvin | ||||
| Organization | |||||
| User Reference | |||||
| Section | XBD 11.1.10, 11.2.4, termios.h | ||||
| Page Number | N/A | ||||
| Line Number | N/A | ||||
| Interp Status | --- | ||||
| Final Accepted Text | 0001932:0007223 | ||||
| Summary | 0001932: termios: should cfsetospeed(B0) trigger SIGHUP? | ||||
| Description | It is unclear to me if setting the output baud rate to 0 using cfsetospeed() followed by tcsetattr() should cause SIGHUP to be sent to the controlling process; in particular in the case of a pseudo-terminal. Linux currently does not send SIGHUP in this case, but has a separate, privileged, ioctl (TIOCVHANGUP) which can do so. | ||||
| Desired Action | Clarification as to the intended meaning of "hang up" using the zero baud rate, in particular in the case of a pseudo-terminal. | ||||
| Tags | tc1-2024 | ||||
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The description of tcsetattr() includes:If the output baud rate stored in the termios structure pointed to by termios_p is the zero baud rate, B0, the modem control lines shall no longer be asserted. Normally, this shall disconnect the line. How this applies to a pseudo-terminal would depend on whether the implementation emulates modem control lines or not. The way this is handled in the UNIX conformance tests is that there is a config parameter to say whether or not modem control is supported. Certifications can be done using either hardware terminals or pseudo-terminals for the General Terminal Interface tests, and as far as I'm aware, all certifications that used pseudo-terminals have been done with that parameter set to "N". |
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On page 209 line 7522 section 11.2.4 Control Modes, change:For pseudo-terminals, the input and output baud rates set in the termios structure need not affect the speed of data transmission through the terminal interface. to: For pseudo-terminals, the input and output baud rates set in the termios structure need not affect the speed of data transmission through the terminal interface and setting the output baud rate to B0 need not cause a modem disconnect. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2025-06-24 23:46 | hpa | New Issue | |
| 2025-06-26 11:22 | geoffclare | Note Added: 0007210 | |
| 2025-07-17 16:27 | geoffclare | Note Added: 0007223 | |
| 2025-07-17 16:28 | geoffclare | Note Edited: 0007223 | |
| 2025-07-17 16:28 | geoffclare | Status | New => Resolved |
| 2025-07-17 16:28 | geoffclare | Resolution | Open => Accepted As Marked |
| 2025-07-17 16:28 | geoffclare | Interp Status | => --- |
| 2025-07-17 16:28 | geoffclare | Final Accepted Text | => 0001932:0007223 |
| 2025-07-17 16:29 | geoffclare | Tag Attached: tc1-2024 | |
| 2025-07-31 15:02 | geoffclare | Assigned To | => geoffclare |
| 2025-08-05 11:09 | geoffclare | Status | Resolved => Applied |
