* lstat(2) upon e and + globbing qualifiers
@ 2012-11-09 12:12 Stephane Chazelas
2020-02-21 19:45 ` Stephane Chazelas
0 siblings, 1 reply; 2+ messages in thread
From: Stephane Chazelas @ 2012-11-09 12:12 UTC (permalink / raw)
To: zsh-workers
Hiya.
Adding a "e" or "+" qualifier to a globbing pattern seems to
cause zsh to call an unnecessary lstat(2) for each file. No big
deal, just potential performance improvement here.
There's a side effect though when you have read but not search
permission on a directory:
$ strace -fe lstat zsh -c 'echo 2/*'
2/bar 2/foo
$ strace -fe lstat zsh -c 'echo 2/*(e::)'
lstat("2/foo", 0x7fff95492110) = -1 EACCES (Permission denied)
lstat("2/bar", 0x7fff95492110) = -1 EACCES (Permission denied)
zsh:1: no matches found: 2/*(e::)
(reproduced with 5.0 on debian)
--
Stephane
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: lstat(2) upon e and + globbing qualifiers
2012-11-09 12:12 lstat(2) upon e and + globbing qualifiers Stephane Chazelas
@ 2020-02-21 19:45 ` Stephane Chazelas
0 siblings, 0 replies; 2+ messages in thread
From: Stephane Chazelas @ 2020-02-21 19:45 UTC (permalink / raw)
To: zsh-workers
Ping:
2012-11-09 12:12:37 +0000, Stephane Chazelas:
Adding a "e" or "+" qualifier to a globbing pattern seems to
cause zsh to call an unnecessary lstat(2) for each file. No big
deal, just potential performance improvement here.
There's a side effect though when you have read but not search
permission on a directory:
$ strace -fe lstat zsh -c 'echo 2/*'
2/bar 2/foo
$ strace -fe lstat zsh -c 'echo 2/*(e::)'
lstat("2/foo", 0x7fff95492110) = -1 EACCES (Permission denied)
lstat("2/bar", 0x7fff95492110) = -1 EACCES (Permission denied)
zsh:1: no matches found: 2/*(e::)
(reproduced with 5.0 on debian)
--
Stephane
^ permalink raw reply [flat|nested] 2+ messages in thread
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