How does strtok_s tokenize a char*?

It seems to have modified the original string that I wanted to split specifying tokens.

how does it return back a substring if i开发者_如何转开发t can't copy from memory?

I'm also looking for an alternative that accepts a const char* Or doesn't modify the orignal string.

Or is it safe to just const_cast the string to remove the const property and let it be handled by strtok_s(char*, const char*, char**).?

strtok_s et al do modify the strings passed in, so no, you can't pass in a const_castd constant string. What it does is if it finds a delimiter, it replaces that delimiter with a NUL terminator to separate the string into two pieces. It then returns a pointer to the first part, which is now the desired null-terminated token.

If you don't want to modify the original string, you can always copy it first and then strtok_s it.