private Structure createUniqueStructure(int size) {
		ProgramBasedDataTypeManager dtm = currentProgram.getDataTypeManager();
		String structName = dtm.getUniqueName(new CategoryPath(DEFAULT_CATEGORY), DEFAULT_BASENAME);
		StructureDataType dt =
			new StructureDataType(new CategoryPath(DEFAULT_CATEGORY), structName, size, dtm);
		return dt;
	}
Create a new structure of a given size and unique generated name within the DEFAULT_CATEGORY. 

@param size is the desired structure size
@return the new Structure
Ghidra/Features/Decompiler/src/main/java/ghidra/app/decompiler/util/FillOutStructureHelper.java