<HTML dir=ltr><HEAD><TITLE>Re: [postgis-users] 1.3.3 Pre-Release Notice</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>I don't know - I would think if you did change no SRID to 0, then instead of ignoring -1, we should have it blow up in people's faces at the PostGIS layer if they explicitly try to set it to that with a "This is not a valid SRID rather than casting to unknown" . That will get them used to the new convention. </FONT></DIV>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Perhaps its a bit militant, but its better than some strange -1 check dangling in the code (and risking a potential segfault that Mark mentioned). You don't want people wondering down the road who are used to 0 seeing -1 and scratching their heads - "What is this -1 doing here? Why aren't we ignoring all negative SRIDs".</FONT></DIV>
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<DIV dir=ltr><FONT face=Arial size=2>R.</FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> postgis-users-bounces@postgis.refractions.net on behalf of Paul Ramsey<BR><B>Sent:</B> Wed 4/9/2008 12:10 PM<BR><B>To:</B> PostGIS Users Discussion<BR><B>Subject:</B> Re: [postgis-users] 1.3.3 Pre-Release Notice<BR></FONT><BR></DIV>
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<P><FONT size=2>Regina,<BR><BR>Actually this logic is good, very old and hasn't worked since it was<BR>written, but good. Because if I ever want to change the value of "no<BR>SRID" from -1 to 0 (and I *do* want to) then having "undefined"<BR>generated as truly undefined is helpful to that end.<BR><BR>P.<BR><BR>On Wed, Apr 9, 2008 at 9:02 AM, Obe, Regina <robe.dnd@cityofboston.gov> wrote:<BR>> This may be a dumb question, but why can't we just skip the strcmp<BR>> altogether?<BR>><BR>> I mean if you do<BR>><BR>> if (sr_id)<BR>><BR>> and someone did happen to explicity set their sr_id = "-1"<BR>><BR>> then what happens<BR>><BR>> "SRID=-1;"<BR>><BR>> Isn't that still legal and gets kicked out by Postgis anyway.<BR>><BR>><BR>> Thanks,<BR>> Regina<BR>><BR>> -----Original Message-----<BR>> From: postgis-users-bounces@postgis.refractions.net<BR>> [<A href="mailto:postgis-users-bounces@postgis.refractions.net">mailto:postgis-users-bounces@postgis.refractions.net</A>] On Behalf Of Paul<BR>> Ramsey<BR>><BR>> Sent: Wednesday, April 09, 2008 11:23 AM<BR>> To: PostGIS Users Discussion<BR>> Subject: Re: [postgis-users] 1.3.3 Pre-Release Notice<BR>><BR>><BR>><BR>> > if ( sr_id && strcmp(sr_id,"-1") ) printf("SRID=%s;", sr_id);<BR>> ><BR>> > I have a very strong feeling that evaluation order in C is<BR>> unspecified, rather<BR>> > than being from left to right; so for example the compiler could<BR>> decide to<BR>> > generate code that evaluates the strcmp() first, in which case it<BR>> would<BR>> > segfault on a NULL :( I think you would need to re-write something<BR>> like this:<BR>><BR>> Should be fine: man -S7 operator<BR>><BR>> > if (sr_id)<BR>> > if (strcmp(sr_id,"-1") ) printf("SRID=%s;", sr_id);<BR>> ><BR>> > (looks even closer...)<BR>><BR>> > In fact, why is sr_id stored as a string anyway? We should make sr_id<BR>> an<BR>> > integer with a default value of -1, and then use sscanf() within the<BR>> switch()<BR>> > statement of pgis_getopt() to read its value.<BR>><BR>> I'll have a look at that, how is the estimated_extent investigation<BR>> coming?<BR>><BR>> _______________________________________________<BR>> postgis-users mailing list<BR>> postgis-users@postgis.refractions.net<BR>> <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>><BR>> -----------------------------------------<BR>> The substance of this message, including any attachments, may be<BR>> confidential, legally privileged and/or exempt from disclosure<BR>> pursuant to Massachusetts law. It is intended<BR>> solely for the addressee. If you received this in error, please<BR>> contact the sender and delete the material from any computer.<BR>><BR>><BR>><BR>> _______________________________________________<BR>> postgis-users mailing list<BR>> postgis-users@postgis.refractions.net<BR>> <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>><BR>_______________________________________________<BR>postgis-users mailing list<BR>postgis-users@postgis.refractions.net<BR><A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR></FONT></P></DIV></BODY></HTML>