astChrCaseastChrCase - Convert a string to upper or lower case

Description:
This function converts a supplied string to upper or lower case, storing the result in a supplied buffer. The astStringCaseastStringCase function is similar, but stores the result in a dynamically allocated buffer.
Synopsis:
void astChrCase( const char $*$in, char $*$out, int upper, int blen, int $*$status )
Parameters:
in
Pointer to the null terminated string to be converted. If this is NULL, the supplied contents of the "out" string are used as the input string.
out
Pointer to the buffer to receive the converted string. The length of this buffer is given by "blen". If NULL is supplied for "in", then the supplied contents of "out" are converted and written back into "out" over-writing the supplied contents.
upper
If non-zero, the string is converted to upper case. Otherwise it is converted to lower case.
blen
The length of the output buffer. Ignored if "in" is NULL. No more than "blen - 1" characters will be copied from "in" to "out", and a terminating null character will then be added.