[geos-devel] GEOS and VC++ 2005

Charlie Savage cfis at interserv.com
Sat Jan 7 19:09:20 EST 2006

Hi everyone,

I'm trying to compile GEOS HEAD using Visual C++ 2005.  I had to patch a 
couple files, which I explain below (patch is also attached below).

There is however a more fundamental issue which is setting up the right 
exports for libgeos.dll.  This is generally done via 
dllexport/dllimport, just like in libgeos_c.  Since libgeos.dll exports 
C++ classes, you can dllexport all the classes.  Of course any such 
exported classes can only be used by code compiled by VC++ due to C++ 
name mangling.  The same if also true if you are using any other 
compiler, for example MingW, to build libgeos.dll - it can only be 
linked against by MinGW.

Anyway, there are few solutions.  First, do nothing and disallow the 
creation of dlls using VC++ (you could build static libraries instead).  
Second, add the right dllExport/dllImport macros to the class 
definitions.  Third, and what I did, manually construct a def file by 
using information extracted from the dll by dumpbin or the VC++ /MAP 
option.  The third option isn't very good because it is manually 
intensive and fairly brittle - although I suppose you could automate it 
using a fair bit of scripting magic.

Anyway, being able to build geos with VC++ is useful, because it makes 
it easier to build extensions for Ruby and Python, both of which are 
compiled using VC++ on Windows.

Just my two cents.




The following patches are needed to build GEOS with Visual Studio C++ 
2005.  I've tested them against both VC++ and MinGW on Windows.  Note I 
have also created updated Visual Studio C++  if anyone is interested 
(the old that was removed from CVS no longer works).

1.  The main issue is from geomgraph.h, lines 490 and 491:

    EdgeIntersectionListIterator begin() const { return nodeMap.begin(); }
    EdgeIntersectionListIterator end() const { return nodeMap.end(); }


typedef set<EdgeIntersection *, EdgeIntersectionLessThen>::iterator 

VC++ does not compile this because it complains that a non-const 
iterator is being returned from a function that is marked const.  It 
seems to me that VC++ is correct, and this should not be allowed.  The 
fix is easy enough, return an const_iterator (which I called 
EdgeIntersectionListIterator Const) instead of a iterator.  This then 
effects a couple of places in the code.

2.  geos_c.cpp, line 1570.

return (finite(az) && az != DoubleNotANumber);

There is not a finite function, but there is a FINITE macro.  So I 
switched to the macro.

3.  GeometricShapeFactory, line 202

    if (angSize <= 0.0 || angSize > 2 * M_PI) //3.14159265358979

M_PI does not seem defined on Windows, so I defined it at the top of the 




Index: source/geomgraph/EdgeIntersectionList.cpp
RCS file: /home/cvs/postgis/geos/source/geomgraph/EdgeIntersectionList.cpp,v
retrieving revision 1.16
diff -u -r1.16 EdgeIntersectionList.cpp
--- source/geomgraph/EdgeIntersectionList.cpp    8 Dec 2005 01:11:29 
-0000    1.16
+++ source/geomgraph/EdgeIntersectionList.cpp    7 Jan 2006 23:48:53 -0000
@@ -65,7 +65,7 @@
 EdgeIntersectionList::isIntersection(const Coordinate& pt) const
-    EdgeIntersectionListIterator it=nodeMap.begin(), endIt=nodeMap.end();
+    EdgeIntersectionListIteratorConst it=nodeMap.begin(), 
     for (; it!=endIt; ++it)
         EdgeIntersection *ei=*it;
@@ -158,7 +158,7 @@
 EdgeIntersectionList::print() const
     string out="Intersections: ";
-    EdgeIntersectionListIterator it=begin(), endIt=end();
+    EdgeIntersectionListIteratorConst it=begin(), endIt=end();
     for (; it!=endIt; ++it) {
         EdgeIntersection *ei=*it;
Index: source/util/GeometricShapeFactory.cpp
RCS file: /home/cvs/postgis/geos/source/util/GeometricShapeFactory.cpp,v
retrieving revision 1.8
diff -u -r1.8 GeometricShapeFactory.cpp
--- source/util/GeometricShapeFactory.cpp    8 Dec 2004 13:54:44 
-0000    1.8
+++ source/util/GeometricShapeFactory.cpp    7 Jan 2006 23:48:53 -0000
@@ -17,6 +17,10 @@
 #include <geos/util.h>
 #include <stdio.h>
+#ifndef M_PI
+#define M_PI        3.14159265358979323846
 namespace geos {
Index: source/headers/geos/geomgraph.h
RCS file: /home/cvs/postgis/geos/source/headers/geos/geomgraph.h,v
retrieving revision 1.26
diff -u -r1.26 geomgraph.h
--- source/headers/geos/geomgraph.h    7 Dec 2005 19:18:23 -0000    1.26
+++ source/headers/geos/geomgraph.h    7 Jan 2006 23:48:53 -0000
@@ -464,6 +464,7 @@
 typedef set<EdgeIntersection *, EdgeIntersectionLessThen>::iterator 
+typedef set<EdgeIntersection *, 
EdgeIntersectionLessThen>::const_iterator EdgeIntersectionListIteratorConst;
  * A list of edge intersections along an Edge.
@@ -486,8 +487,8 @@
     EdgeIntersectionListIterator begin() { return nodeMap.begin(); }
     EdgeIntersectionListIterator end() { return nodeMap.end(); }
-    EdgeIntersectionListIterator begin() const { return nodeMap.begin(); }
-    EdgeIntersectionListIterator end() const { return nodeMap.end(); }
+    EdgeIntersectionListIteratorConst begin() const { return 
nodeMap.begin(); }
+    EdgeIntersectionListIteratorConst end() const { return nodeMap.end(); }
     bool isEmpty() const;
     bool isIntersection(const Coordinate& pt) const;
Index: source/capi/geos_c.cpp
RCS file: /home/cvs/postgis/geos/source/capi/geos_c.cpp,v
retrieving revision 1.19
diff -u -r1.19 geos_c.cpp
--- source/capi/geos_c.cpp    13 Dec 2005 23:03:25 -0000    1.19
+++ source/capi/geos_c.cpp    7 Jan 2006 23:48:53 -0000
@@ -1567,7 +1567,7 @@
     double az = g->getCoordinate()->z;
     //sprintf(msg, "ZCoord: %g", az);
-    return (finite(az) && az != DoubleNotANumber);
+    return (FINITE(az) && az != DoubleNotANumber);

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