[luatex] os.execute

[Hans Hagen]

On 11/28/2015 9:39 PM, Reinhard Kotucha wrote:
> On 2015-11-28 at 15:08:43 +0100, luigi scarso wrote:
>
>   > On Sat, Nov 28, 2015 at 10:14 AM, Dirk Laurie <dirk.laurie at gmail.com> wrote:
>   >
>   >     In Lua 5.2, the definition of os.execute changed to:
>   >
>   >     This function is equivalent to the ISO C function system. It passes
>   >     command to be executed by an operating system shell. Its first result
>   >     is true if the command terminated successfully, or nil otherwise.
>   >     After this first result the function returns a string and a number, as
>   >     follows:
>   >
>   >     "exit": the command terminated normally; the following number is the
>   >     exit status of the command.
>   >     "signal": the command was terminated by a signal; the following number
>   >     is the signal that terminated the command.
>   >
>   >     When called without a command, os.execute returns a boolean that is
>   >     true if a shell is available.
>   >
>   >     In Lua 5.1, it was:
>   >
>   >     This function is equivalent to the C function system. It passes
>   >     command to be executed by an operating system shell. It returns a
>   >     status code, which is system-dependent. If command is absent, then it
>   >     returns nonzero if a shell is available and zero otherwise.
>   >
>   >     In LuaTeX, Version beta-0.76.0-2013121407  (TeX Live 2013/dev/Debian),
>   >     _VERSION is "Lua 5.2" but os.execute still behaves as in Lua 5.1.
>   >
>   >     Is this still true in Version 0.85.0? If so, is it a policy decision
>   >     that one can rely on?
>   >
>   > Thank you for the report.
>   > We are seeing if we can jump to 5.3,
>   > at some moment we will review also os.execute.
>
> Hi Luigi,
> as far as signals are concerned, I don't know whether they are
> properly supported by Windows.  Honestly, I doubt.  Thus I recommend
> to test them with stock Lua on various versions of Windows before
> adapting LuaTeX.

we might just as well keep the current implementation as it also needs 
to hook in security options so we don't have to follow stock lua here; 
one can always wrap os.execute into something that does what one wants

Hans

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