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Diffstat (limited to 'Doc/Zsh/mod_system.yo')
| -rw-r--r-- | Doc/Zsh/mod_system.yo | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/Doc/Zsh/mod_system.yo b/Doc/Zsh/mod_system.yo index a27bab47f..3a85e760f 100644 --- a/Doc/Zsh/mod_system.yo +++ b/Doc/Zsh/mod_system.yo @@ -177,8 +177,11 @@ locked by opening a file descriptor to the file and applying a lock to the file descriptor. The lock terminates when the shell process that created the lock exits; it is therefore often convenient to create file locks within subshells, since the lock is automatically released when -the subshell exits. Status 0 is returned if the lock succeeds, else -status 1. +the subshell exits. Note that use of the tt(print) builtin with the +tt(-u) option will, as a side effect, release the lock, as will redirection +to the file in the shell holding the lock. To work around this use a +subshell, e.g. `tt((print message) >> )var(file)'. Status 0 is +returned if the lock succeeds, else status 1. In the second form the file descriptor given by the arithmetic expression var(fd_expr) is closed, releasing a lock. The file descriptor |