As an example, the differences of times computed below are obviously wrong
(+04:00 and -04:00 are mixed up). More annoying, the function date:seconds(),
which should return the same value as time(NULL), may be wrong when
date:date-time() returns a non GMT date...).


[pesenti@dev vivisimo]$ cat /tmp/a.xsl
<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"
   xmlns:date="http://exslt.org/dates-and-times"
   extension-element-prefixes="date"
>
<xsl:template match="/">
  <xsl:value-of select="date:difference('1970-01-01T00:00:00+04:00',
'1970-01-01T04:00:00Z')"/>
  <br/>
  <xsl:value-of select="date:difference('1970-01-01T00:00:00-04:00',
'1970-01-01T04:00:00Z')"/>
</xsl:template>

</xsl:stylesheet>

[pesenti@dev vivisimo]$ xsltproc /tmp/a.xsl /tmp/a.xsl
<?xml version="1.0"?>
P0D<br/>PT8H

[pesenti@dev vivisimo]$ cat /tmp/b.xsl
<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"
   xmlns:date="http://exslt.org/dates-and-times"
   extension-element-prefixes="date"
>
<xsl:template match="/">
  <xsl:value-of select="date:seconds()"/>
</xsl:template>

</xsl:stylesheet>
[pesenti@dev vivisimo]$ xsltproc /tmp/b.xsl /tmp/b.xsl
<?xml version="1.0"?>
1095485514
[pesenti@dev vivisimo]$ date +'%s'
1095514317
[pesenti@dev vivisimo]$


[pesenti@dev vivisimo]$ xsltproc --version
Using libxml 20611, libxslt 10108 and libexslt 806
xsltproc was compiled against libxml 20611, libxslt 10108 and libexslt 806
libxslt 10108 was compiled against libxml 20611
libexslt 806 was compiled against libxml 20611