diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/Zsh/builtins.yo | 16 | ||||
| -rw-r--r-- | Doc/Zsh/options.yo | 8 |
2 files changed, 20 insertions, 4 deletions
diff --git a/Doc/Zsh/builtins.yo b/Doc/Zsh/builtins.yo index 46f40cc3a..edc335e8b 100644 --- a/Doc/Zsh/builtins.yo +++ b/Doc/Zsh/builtins.yo @@ -2059,6 +2059,22 @@ then all currently active child processes are waited for. Each var(job) can be either a job specification or the process ID of a job in the job table. The exit status from this command is that of the job waited for. + +It is possible to wait for recent processes (specified by process ID, +not by job) that were running in the background even if the process has +exited. Typically the process ID will be recorded by capturing the +value of the variable tt($!) immediately after the process has been +started. There is a limit on the number of process IDs remembered by +the shell; this is given by the value of the system configuration +parameter tt(CHILD_MAX). When this limit is reached, older process IDs +are discarded, least recently started processes first. + +Note there is no protection against the process ID wrapping, i.e. if the +wait is not executed soon enough there is a chance the process waited +for is the wrong one. A conflict implies both process IDs have been +generated by the shell, as other processes are not recorded, and that +the user is potentially interested in both, so this problem is intrinsic +to process IDs. ) findex(whence) item(tt(whence) [ tt(-vcwfpams) ] var(name) ...)( diff --git a/Doc/Zsh/options.yo b/Doc/Zsh/options.yo index 068a253ac..452b258b4 100644 --- a/Doc/Zsh/options.yo +++ b/Doc/Zsh/options.yo @@ -1434,10 +1434,10 @@ shell is saved for output within a subshell (for example, within a pipeline). When the option is set, the output of tt(jobs) is empty until a job is started within the subshell. -When the option is set, it becomes possible to use the tt(wait) builtin to -wait for the last job started in the background (as given by tt($!)) even -if that job has already exited. This works even if the option is turned -on temporarily around the use of the tt(wait) builtin. +In previous versions of the shell, it was necessary to enable +tt(POSIX_JOBS) in order for the builtin command tt(wait) to return the +status of background jobs that had already exited. This is no longer +the case. ) enditem() |