Q61189: C 6.00 README: The sizeof Operator Return Value

Article: Q61189
Product(s): See article
Version(s): 6.00   | 6.00
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 25-APR-1990

The sizeof Operator Return Value
--------------------------------

To comply with ANSI specifications, the sizeof operator now returns an
unsigned int rather than an int. This may cause problems in statements
of the following form:

   -sizeof( expression )

For example, the following line of code, used to position a file
pointer one record from the end, no longer works:

   fseek( file, (long)(-sizeof( record )), SEEK_END );

Because sizeof returns an unsigned int, the record size is zero-
extended to a long value rather than sign-extended to the appropriate
signed value.

To avoid this problem, you can cast the record size to a long before
you negate it, as follows:

   fseek( file, -((long)sizeof( record )), SEEK_END );

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