[Mapserver-users] why a segfault with mapserv but shp2img works fine?

[Daniel Morissette]

Sean Gillies wrote:
> 
> I've built mapserv and shp2img from a very recent CVS checkout.  While
> testing, I've found that shp2img works fine with my map file.  However,
> when testing mapserv from the shell using the REQUEST_METHOD and
> QUERY_STRING environmental variables (same map file), I get a
> segmentation fault.  My map has a single raster layer, a GeoTIFF that
> I'm accessing with GDAL.
> 
> Can anyone briefly summarize the differences in the way shp2img and
> mapserv work, and why the latter might be more prone to a segfault?
> 

Well, mapserv does all sorts of things that shp2img doesn't worry
about.  Think about all the template stuff (were you using mode=map or
the default mode=browse ?), the QUERY_STRING parsing, turning layers on
and off, temporary image files creation for elements found in the
template, etc.

A crash is always an important thing to fix IMO.  If you can get a stack
dump in GDB after the crash and provide more details to reproduce it
then please file a bug in bugzilla with all that information.

BTW, there is a (undocumented) way to test with mapserv at the
command-line without having to set the QUERY_STRING and REQUEST_METHOD
env. vars.  You can use this:

  ./mapserv "QUERY_STRING=map=/path/to/mymap.map&mode=map&..."

Daniel
-- 
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 Daniel Morissette               morissette at dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
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