Use this function to copy a string inside an AFC string_new. This afc_string_copy() is advanced considering the usual C strcpy command: it does bound checking so you don't have to do any control before copying.
Destination string. This string MUST be an AFC string_new created using @{" afc_string_new() " LINK afctools_string}
Source string. This string can be anything, a static string, a AFC string_new, a memory area...
Here you can specify how many chars to copy. Pass the value *ALL* to copy the whole string.