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[Bug 11682] under-specification of func-available-environment-variables and unc-available-environment-variable

From: <bugzilla@jessica.w3.org>
Date: Tue, 11 Jan 2011 03:43:23 +0000
To: public-qt-comments@w3.org
Message-Id: <E1PcV8l-0002Gr-Ud@jessica.w3.org>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=11682

Liam R E Quin <liam@w3.org> changed:

           What    |Removed                     |Added
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                 CC|                            |liam@w3.org

--- Comment #7 from Liam R E Quin <liam@w3.org> 2011-01-11 03:43:22 UTC ---
| So what are environment variables ? Operating system-related variables ?
| Process-related  ? Implementation -defined completely ?

The section to which you link gives an explanation, and a reference to POSIX. 
I think it's pretty clear.  It refers to the operating system concept of
environment variables.

| 2. The text implies that the result of such a function call depends of the
| current status of the external environment where the program is executed. As
a
| consequence such a function is nondeterministic, right ?

It's deterministic - stable. But the same query run on two different days might
give two different answers, just as with functions to get the current date.

| 3. The text also implies that the invocation of XQuery external functions
could
| have side effects on the external environment. Shouldn't this better be left
to
| XQuery scripting ? Such a note can only add confusion.

No. Consider the external function "putenv" to set a system environment
variable.

| 4. In general, I am not convinced that such a function should be standardized
| and imposed to all XQuery processors.

When the Working Group discussed it (in at least 3 calls and an email thread)
enough people felt it was useful, and/or had customers wanting it, or in some
cases already using a comparable facility, that it was added.

In C or C++ on any POSIX-complaint system you could use the getenv() function
to implement this feature.  That includes everything from MS-DOS through Unix
and Linux and OS X to Windows, as well as mobile platforms. Java systems would
probably map this to system properties.

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Received on Tuesday, 11 January 2011 03:43:25 UTC

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