[ARX]求助捕捉的问题

hunanoh

小弟最近想编写程序完成以下功能：创建一个点，并设置好捕捉方式，为以后的选取做好准备，但就是行不通，望哪位大虾有空指点一下。

void ARXgetosnappoints()
{
 AcDbPoint *p1 = new AcDbPoint(AcGePoint3d(0.0, 0.0, 0.0));

 AcDbBlockTable *pBlockTable;
 acdbHostApplicationServices()->workingDatabase()
  ->getSymbolTable(pBlockTable, AcDb::kForRead);
 AcDbBlockTableRecord *pBlockTableRecord;
 pBlockTable->getAt(ACDB_MODEL_SPACE, pBlockTableRecord, AcDb::kForWrite);
 pBlockTable->close();

 pBlockTableRecord->appendAcDbEntity(p1);
 pBlockTableRecord->close();

 int gsSelectionMark;
 AcGePoint3d pickPoint;
 AcGePoint3d lastPoint;
 AcGeMatrix3d viewXform;
 AcGePoint3dArray snapPoints;
 AcDbIntArray geomIds;
  
 p1->getOsnapPoints(
  AcDb::kOsModeNear,
  gsSelectionMark,
  pickPoint,
  lastPoint,
  viewXform,
  snapPoints,
  geomIds);

 ads_point result;
 acedGetPoint(NULL, "请选择一个点：", result);

 p1->close();
}