The following issue has been SUBMITTED.
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http://austingroupbugs.net/view.php?id=1212
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Reported By: kre
Assigned To:
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Project: 1003.1(2016)/Issue7+TC2
Issue ID: 1212
Category: Shell and Utilities
Type: Enhancement Request
Severity: Objection
Priority: normal
Status: New
Name: Robert Elz
Organization:
User Reference:
Section: XCU 2.14 -- trap special builtin
Page Number: 2420 - 2423
Line Number: 77484-5 (and more)
Interp Status: ---
Final Accepted Text:
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Date Submitted: 2018-09-28 02:56 UTC
Last Modified: 2018-09-28 02:56 UTC
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Summary: Enhance trap command
Description:
The trap command, as it stands, is missing two useful functions
1) the ability to discover the current action for a particular condition
2) the ability to save the current state of all conditions (see issue
1211)
Several shells have implemented a solution to (1) using a new -p option
to trap (unfortunately, the output format, and so how it should be used,
varies - but at least the mechanism is there).
The NetBSD shell has a solution to (2) based upon that for (1), but as
far as I know, no other shell has a solution to this, and the NetBSD shell
is not in widespread enough use to standardise its mechanism yet.
Hence, I am requesting that this issue be marked as "for the future" and
retained (along with any notes it attracts, and possible different
solutions)
until we do have something that is ready to be included in the standard.
And implementers - please do *something*...
Also note, that for shells that have "trap -p" already, but treat it
used with no conditions as identical to "trap" with no operands, that
is not a useful feature (two ways to do the same thing) and changing the
implementation of "trap -p" as suggested below will do no harm.
Desired Action:
In the SYNOPSIS, between lines 77484 and 77485 add a new form for the
command
trap -p [condition...]
Then somewhere in the DESCRIPTION (probably after the paragraph about
trap with no operands, starting on line 77514) add a new paragraph
When the -p option is given the trap command shall write,
in the same format used when no operands are given, a list
of commands for each condition specified as an operand, or if
no operands, other than the -p flag, are given, then for all
possible conditions for which actions can be set in the shell,
whether currently at their default values,or not. It is unspecified
whether the values for SIGKILL and SIGSTOP can be obtained this way,
but if those are included in trap -p output, the shell shall not
object to them used as input provided that the action specified
is the same as was, or would be, output by trap -p, and in this case
no undefined results shall occur.
Then change the example at line 77524 from
save_traps=$(trap)
to
save_traps=$(trap -p)
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Issue History
Date Modified Username Field Change
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2018-09-28 02:56 kre New Issue
2018-09-28 02:56 kre Name => Robert Elz
2018-09-28 02:56 kre Section => XCU 2.14 -- trap
special builtin
2018-09-28 02:56 kre Page Number => 2420 - 2423
2018-09-28 02:56 kre Line Number => 77484-5 (and more)
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