# $ K + Selecting a GPD file for editing
The GPD file editor can be launched in several ways:
·	The GPD file can be selected from the Model Information list in the Workspace Editor.
·	An existing GPD file can be opened from the File Open dialog.
·	A GPD file can be double-clicked in the Windows Explorer.
·	A new (empty) GPD file can be created from the File / New menu item/toolbar button.
If a file is launched via the first method, any cached error log for the GPD file will be restored.  Otherwise, the editor will begin with no errors detected.

# $ K + The error log and the error bar
There are two common operations performed with GPD files during the minidriver creation process:
1.	Generation of the original GPD file from GPC data.
2.	Syntax checking of the GPD file as it is edited.
Each of these operations may produce an error log.  If one is produced, the GPD editor displays its contents using the error bar.
Messages produced by the converter
The converter issues messages to the error log that are global in scope.  These messages do not give the location of an error, or even tell you how many times the condition the message refers to was detected. 
The converter does provide some localized information in the form of source code comments in the GPD file itself.  To aid in identifying these, they are colored yellow and red (for warning and error comments, respectively).  In most cases, the message gives a keyword you can use with the Find capability (F3) to locate the potential errors or hazardous conditions.
The screen snapshot on the next page shows a set of messages, and a comment which is related to the first message.
Messages produced by the syntax checker
Error messages produced by the syntax checker often contain location information (file name and line number).  The editor will use this information if it exists to point you to the lines with the error information in them.
In many cases, though (such as a missing required global keyword), no location information Is available.  In such cases, you will need to understand and fix the bug without line number information.

# $ K + Editing a GPD file
{bml GPDEDIT.SHG}
A GPD editor window, with the error bar shown.  Click where the cursor changes to a hand for further information.
The GPD file editor is a simple text editor based upon the Rich Edit common control.  It has support for the commonest editing features, including Find/Replace, and cut and paste.  No undo capability exists in this editor.
Comments are color coded- the error and warning comments produced by the GPC to GPD converter are colored red and yellow, respectively, while ordinary comments are green.
The title bar will contain the file name if the GPD is opened from the File Open menu item or toolbar button.  However, if it is opened from the workspace editor, the title bar will read <Workspace name> : <Model Name>, instead.
At the base of the editor window is a status bar, used to display messages and the current line and column.  If there are error or warning messages from the most recent conversion or syntax check , the GPD error control will be placed just above the status bar in the window, as illustrated above.  

# $ Comment Coloring
Comments like these are colored to make them easier to identify.  Most comments will be colored green.  Warning and error comments from the GPC to GPD converter are yellow and red, respectively.

# $ Previous and Next Error buttons
Use these buttons to navigate the error list.  If the newly selected error contains line number information for the GPD file that you are editing, the editor will automatically scroll to the line the error was reported on.
If you are at the beginning or end of the list, the appropriate button will be disabled.
Keyboard:  F4 / Shift+F4 for previous/next.  The mnemonic accelerators also work.

# $ Fixed Error button
This button can be used to remove the selected error from the error log.  This allows you to use the log as a “to-do” list, particularly after the GPC to GPD converter has been run.

# $ Error log
This is a list of all of the error and warning messages logged either from the GPC to GPD converter (the initial log), or from the most recent syntax check.  See Syntax Checking GPD files .
This list can be navigated with the error buttons .

# $ Currently selected error
The first pane of the status bar will always contain the text of the currently selected error.

# $ Selection Indicator
This indicator on the status bar indicates where the currently selected text ends, or where the insertion point is located if there is no selected text.

# $ K + Syntax Checking GPD files
To syntax check a single GPD file:
·	Open the GPD file, either from the workspace editor, or from the File Open menu item or toolbar button..
·	Select the File/Syntax Check menu item, or press the button, which looks like this:{bmc gpdcheck.bmp}
To syntax check all of the GPD files associated with a workspace (this is a good idea just before you finish with the workspace):
·	Open the workspace, or make its editor window active, if it is already opened.
·	Select the File/Syntax Check all GPDs menu item, or press the tool bar button, which looks like this:{bmc gpdcheck.bmp}
Once the syntax check is completed, you will have a chance to browse the errors, if there were any.