Q43062: Incorrect Code Generated with Conditional Operator

Article: Q43062
Product(s): See article
Version(s): 5.00 5.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | buglist5.10 | mspl13_c
Last Modified: 16-JAN-1990

Using the conditional with incremental operators on pointers can
generate incorrect code. The following routine should reset ptr to the
beginning of the list if the end of the list has been reached. If the
end of the list has not been reached, ptr should be incremented. The
code generated does not increment ptr as expected; ptr is actually
reset to itself, i.e., ptr = ptr.

Replacing the ternary operator (? :) with an if -- else construct
corrects the problem.

Microsoft is researching this problem and will post new information as
it becomes available.
The following routine illustrates this behavior:

test()
{
        char *ptr,*str,*end;

        ptr = ((ptr == end)? str: ptr++);

}

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