[gdal-dev] Need help if OGR C-API (Resolved)

[Even Rouault]

Ah ok, but I wasn't refering to that. I meant that you shouldn't do 
OGR_FD_Release( hFDefnIn ) on a field definition returned by 
OGR_L_GetLayerDefn(), otherwise you'll get into memory corruption issues.

Le samedi 04 septembre 2010 05:17:38, Stephen Woodbridge a écrit :
> Thank you, still learning my way around things.
> 
> So after copying 90% of the my not working source code into the test
> program and it worked there, it finally dawned on me to check the
> Makefile. Duh! while I had removed all the shapelib calls from the
> source code, I forgot to check the link line to remove adding -lshp
> which apparently was causing the bogus behavior. Cleaned that up and
> things started working as expected.
> 
> Thanks for all the help guys. It is very much appreciated.
> 
> -Steve
> 
> On 9/3/2010 2:20 PM, Even Rouault wrote:
> > Stephen
> > 
> > did you read :
> > http://gdal.org/ogr/ogr__api_8h.html#7b67ea4ab5892c6720460dc7f66eca2d ?
> > 
> > You'll know the cause of the crash afterwards ;-)
> > 
> > Le vendredi 03 septembre 2010 20:12:51, Stephen Woodbridge a écrit :
> >> Even,
> >> 
> >> Here is my test program:
> >> 
> >> $ cat testogr.c
> >> #include "ogr_api.h"
> >> 
> >> int main() {
> >> 
> >>       OGRDataSourceH hDSin;
> >>       OGRLayerH hLayerIn;
> >>       OGRFeatureDefnH hFDefnIn;
> >>       OGRwkbGeometryType layerGeomType;
> >>       
> >>       OGRRegisterAll();
> >>       
> >>       hDSin = OGROpen( "/u/data/routeloops-v2/25/25017/Streets.shp",
> >> 
> >> FALSE, NULL );
> >> 
> >>       hLayerIn = OGR_DS_GetLayerByName( hDSin, "Streets" );
> >>       
> >>       hFDefnIn = OGR_L_GetLayerDefn( hLayerIn );
> >>       layerGeomType = OGR_FD_GetGeomType( hFDefnIn );
> >>       printf("GeometryType: %s\n", OGRGeometryTypeToName( layerGeomType
> >>       ));
> >>       
> >>       OGR_FD_Release( hFDefnIn );
> >>       OGR_DS_Destroy( hDSin );
> >> 
> >> }
> >> 
> >> $ gcc -g -o testogr testogr.c  -I/usr/local/include/gdal -lgdal -lm
> >> 
> >> It reports GeometryType correctly and then segvs :(
> >> 
> >> woodbri at mappy:~/work$ gdb ./testogr
> >> GNU gdb 6.8-debian
> >> Copyright (C) 2008 Free Software Foundation, Inc.
> >> License GPLv3+: GNU GPL version 3 or later
> >> <http://gnu.org/licenses/gpl.html>
> >> This is free software: you are free to change and redistribute it.
> >> There is NO WARRANTY, to the extent permitted by law.  Type "show
> >> copying" and "show warranty" for details.
> >> This GDB was configured as "x86_64-linux-gnu"...
> >> (gdb) run
> >> Starting program: /home/woodbri/work/testogr
> >> [Thread debugging using libthread_db enabled]
> >> warning: Lowest section in /usr/lib/libicudata.so.38 is .hash at
> >> 0000000000000120
> >> GeometryType: Line String
> >> [New Thread 0x7f361a0bc710 (LWP 30585)]
> >> 
> >> Program received signal SIGSEGV, Segmentation fault.
> >> [Switching to Thread 0x7f361a0bc710 (LWP 30585)]
> >> 0x0000000000000031 in ?? ()
> >> (gdb) bt
> >> #0  0x0000000000000031 in ?? ()
> >> #1  0x00007f3619a2f190 in ~OGRShapeLayer (this=0x605a40)
> >> 
> >>       at ogrshapelayer.cpp:105
> >> 
> >> #2  0x00007f3619a2c63f in ~OGRShapeDataSource (this=0x604330)
> >> 
> >>       at ogrshapedatasource.cpp:62
> >> 
> >> #3  0x0000000000400958 in main () at testogr.c:19
> 
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