FYI,
The following code in the sc_for_req_header function in module jk_ajp_common
was getting a pointer error on version V5R4 of i5/OS (AS400).
while (*p)
header[i++] = toupper((unsigned char)*p++);
IBM provided two solutions to this problem.
I tried the 2nd solution of wrapping the toupper in parenthesis and the code
works correctly when compiled with LOCALE(*LOCALEUTF).
IBM's explanation. . .
The reason for the different behavior is that the toupper() routine is
implemented as a macro within the header file and the parameter is evaluated
twice for the *LOCALEUTF version of the routine.
The standard indicates that the routines within <ctype.h> may be implemented as
macros - http://www.opengroup.org/onlinepubs/007908799/xsh/ctype.h.html
Any routine which may be implemented as a macro is allowed to evaluate the
parameter any number of times and thus using code like xxx(*p++) where xxx is a
runtime routine is not portable. The standard does not state this for every
routine which may be a macro, but it is true in all macro cases. Here is an
example within the standard which explicitly states this fact for the getc()
routine - http://www.opengroup.org/onlinepubs/007908799/xsh/getc.html . Here
is an excerpt from that web page:
Because it may be implemented as a macro, getc() may treat incorrectly a stream
argument with side effects. In particular, getc(*f++) will not necessarily work
as expected. Therefore, use of this function should be preceded by "#undef
getc" in such situations; fgetc() could also be used.
This yields the following solutions for such code:
1) use #undef toupper after <ctype.h> is included.
2) a second solution is to wrap the toupper call in parenthesis - e.g.
(toupper)((unsigned char)*p++)
Either of these solutions can be used to 'disable' the macro version and allow
both methods to work correctly.
