The following example shows how the Header-to-copy utility translates external data declarations in C source code to their equivalent COBOL copyfile form.
typedef struct _WidgetClassRec *WidgetClass; extern WidgetClass widgetClass;
COBOL output (to .cpy file)
01 WidgetClass is typedef usage data-pointer.
COBOL output (to .ext file):
01 1widgetClass is external by "widgetClass" usage data-pointer.
The names of the type definition and the external data item must be unique for COBOL which is why H2cpy has added a 1 to the front of the data-name. The symbolic name widgetClass is the name to be used by the Linker to resolve the reference to the external data item declared in C.