int QisLib_OpenGDSII(const char* GdsFName);

	GdsFName: Complete path of the GDSII File to be opened.

	success: 0
	failure: one of the following values :

	-1: Qislib has not been initialized.
	-2: The specified GDSII file name is either empty or null.
	-3: The specified GDSII file does not exist.
	-4: The specified file is not a valid GDSII file.
	-5: Internal memory error occurred during scanning.
	-6: Internal memory error occurred during loading.
	-7: Layer error, maximum 2048 different layer numbers allowed.
	-8: Layer error, maximum 256 different data-type numbers allowed.
	-9: Layer error, maximum 65536 different layer:datatype combinations allowed.
	-10: Internal memory error while processing layers.
	-11: This program is not licensed to work with GDSII files.
	-12: No cells have been defined in the specified GDSII file.
	-27: The system does not have enough memory to view this GDSII file.
	-28: Cannot open another file while one is already being opened.

	The following codes returned from the function must not be treated as errors. These
	are just warnings and the GDSII file has been opened successfully.
	-13: Failed to create memory maps due to file i/o error.
	-14: Failed to write GDS data entities into the memory map.
	-15: Internal error occurred while creating memory maps.
	-16: Failed to create memory map due to mismatch in the number of cells
	-17: Failed to write to memory maps.
	-18: Failed to read GDS data entities from the memory map.
	-19: Failed to use memory maps because of cell redefinition.
	-20: Failed to use memory maps because of different layer map settings.
	-21: Failed to use memory maps because version is not supported.
	-22: Failed to use memory maps because file is not supported.
	-23: Failed to use memory maps because the map file is older than the input GDS file.
	-24: Failed to use memory maps due to internal error.
	-25: Failed to use memory maps because load empty references settings have changed.
	-26: Failed to use memory maps because they were created using different memory load settings.

	- Opens,scans and loads a GDSII file.
	- This function can also be used to create memory maps.
	- If a GDSII/OASIS file is already opened, it will be closed.
	- On Unix/Linux, the path is case sensitive.
	- If return code is 0, call QisLib_GetOpenGDSWarnings to get list of warnings
	encountered while opening the input GDS file.The warnings indicate the presence of
	syntax errors in the GDSII file. It is up to the user to treat them as warnings or errors.
	- If the return code is -27, call QisLib_GetErrorMsg to get detailed information on
	the error.
	- Calling QisLib_OpenGDSII while another file open (GDSII or OASIS) is in progress, is
	not permitted and will result in an error code being returned. To open a GDSII file
	while a GDSII/OASIS is already being opened, call QisLib_Stop first.
	- The user can speed up the file open operation by making use of memory maps. Refer
	to QisLib_SetUseMemoryMaps and QisLib_SetCreateMemoryMaps for details.
	- If the file open operation needs to be cancelled, call QisLib_Stop. To use this
	feature, QisLib_SetProcessEvents must be on. Also on Unix/Linux, the program's
	application context must be passed as a parameter to QisLib_InitLib.


Functions that are effective only if they are called before QisLib_OpenGDSII: