Q31009: Protected-Mode C Extensions Fail with "Protection Fault"

Article: Q31009
Product(s): See article
Version(s): 1.00 | 1.00
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | docerr | mspl13_basic
Last Modified: 29-AUG-1988

Problem:
   I am writing C extensions for the protected mode of OS/2. All my
extensions fail with a general-protection fault. The sample program on
Page 85 of the "Microsoft Editor for MS OS/2 and MS-DOS: User's Guide"
also fails.

Response:
   Page 78 of the "Microsoft Editor for MS OS/2 and MS-DOS: User's
Guide" incorrectly states that the second argument is a NULL pointer.
   The programs are crashing because the incorrect value is being
passed to the FileNameToHandle routine. This routine requires a
pointer to a null string, not a null pointer.
   For example, the following statement

   cfile=FileNameTohandle("",NULL);

should read as follows:

   cfile=FileNameTohandle("","");

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