[Gdal-dev] Safety check needed for png read

Frank Warmerdam warmerdam at pobox.com
Wed Aug 25 09:42:57 EDT 2004

Ben Discoe wrote:
> While in the png code (chasing GDAL crashes) i found that it calls libpng in
> a very unsafe manner, not checking for failure.  We really need something
> like this in pngdatset.cpp:
>  poDS->hPNG = png_create_read_struct(...);
>  if (poDS->hPNG == NULL)
>  {
>    int version = png_access_version_number();
>    CPLError( CE_Failure, CPLE_NotSupported, 
>      "The PNG driver failed to access libpng with version '%s',"
>      " library is actually version '%d'.\n",
>      PNG_LIBPNG_VER_STRING, version);
>    delete poDS;
>    return NULL;
>  }
> This will informatively catch the situation where the libpng libraries and
> headers are out of sync, which is quite easy to get when wrangling with
> library versioning issues, as i have been for the past 5 hours.


Suggested change applied.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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