Description: FORTRAN: Using WCHAR from FORTRAN
Header: FORTRAN: Using WCHAR from FORTRAN

 This applies to the Apple II, Apple II+, Apple IIe, and  Apple IIc.
 The Turtlegraphics WCHAR procedure, which writes a single character on the
 high-res screen, will often give a "Value Range Error" (S#20, P#17, I#11) when
 called from FORTRAN.  WCHAR does not check the high byte of the character word
 passed before calling the DRAWHBLOCK routine, so if the high byte contains a
 value, WCHAR will choke by trying to access an index beyond the end of
 SYSTEM.CHARSET.

 This error will occur when passing a single character from a character array,
 but not from a single character "string".  For example,

 CHARACTER CH(10)
 READ (*,100) CH(1)
 CALL WCHAR (CH(1))

 will result in a "Value Range Error".  However,

 CHARACTER*1 CH
 READ (*,100) CH
 CALL WCHAR (CH)

 will work correctly.  To prevent the error in the first example, replace the
 call statement with

 CALL WCHAR (CHAR (ICHAR ( CH(1))))

 which will convert the character to a integer, and then back to a character
 before calling WCHAR.
 Apple Tech Notes


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