Re: toupper is not thread safe.

First of all, apologies for the delay in replying to this.

Thanks for reporting this issue, you are correct the way the in-line implementation (provided by ctype.h) uses a global variable which is not thread safe. This issue only applies to the in-line implementation, and the out-of-line (library call) is safe to use in a multi-threaded environment.

To force use of the out-of-line copy, you just need to #undef the appropriate functions after including  ctype.h, for example:

#include <ctype.h>
#undef toupper
#undef tolower

Which will do the equivalent of your own function.

Regards,

Murray