[erlang-questions] Calling halt() only after I/O has completed.

Richard Carlsson <>
Wed Apr 30 09:16:05 CEST 2008

> I have small escript that reads a bunch of files, scans them for data,
> and prints the matches to stdout ('standard_io', to be precise, going
> to the 'user' process under the hood).  If there were any matches,
> then we have an error condition and the escript needs to return a
> status of 1 to the shell.
> If there are only a few matches, things work.  If there are many
> matches, then the main process calls halt(1) while the I/O process is
> still sending the text to the terminal and the output gets truncated.
> The only way I have found to work around this is to insert a delay
> scaled by the number of records (100 ms seems to work).  Calling
>   file:close(user)
> to synchronously close the port and flush the output doesn't work.
> The top-level process just hangs.
> What's the best solution for guaranteeing that all the data gets
> printed before the program exits?  This is with ERTS 5.5.4 on Linux.


Also see Magnus Fröberg's patch posted just a few days ago, to add
a function init:stop(Status), which has been sorely missing.


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