Type casting between char* and UBYTE* (unsigned char*)

Background: I am receiving a array as char* as a part of socket session. Now we have to match the Tokens (HTTP headers) out of it.Code here is that we have created a UBYTE* and getting the value from the char array after typecasting with UBYTE. Later same UBYTE pointer we are passing to other function which accepts char* after typecasting it to char*.

Problem here is this works in release build and not in debug build (with -g and different optimization). Not only this adding few prints in debug mode hide the problem.

So my queestion he开发者_运维技巧re, What is the difference between UByte pointer(which is essentially a unsigned char) and char pointer. Changing UByte to char is solving my problem in all modes but I dont have any explaination for the same? Any thoughts ?

There is nothing wrong with casting between char * and unsigned char *. If you're getting unexpected behavior which varies depending on optimization levels, there's certainly a bug in your code, but it probably has little to do with discarding signedness in the cast.

Aside from that, UBYTE is a pretty ridiculous typedef since there exists a standard C type, uint8_t, which is identical and defined in stdint.h.

Perhaps you could explain in the first place, why you though you had to use an unsigned char in the first place? And what doesn't work means?

void*, char* and unsigned char* have different semantics and you should use them according to that:

• void* points to unspecific data with which you can't do anything unless you cast it to some real type
• char* unfortunately has two different meanings, either as text string, or as unspecific data but which may be addressed (patched) at a low (byte) level
• signed char and unsigned char are small width integers on which you want to perform arithmetics