On Fri, Aug 14, 2020 at 05:24:15PM -0700, Nick Desaulniers wrote: > +#ifndef __HAVE_ARCH_STPCPY > +/** > + * stpcpy - copy a string from src to dest returning a pointer to the new end > + * of dest, including src's NULL terminator. May overrun dest. > + * @dest: pointer to end of string being copied into. Must be large enough > + * to receive copy. > + * @src: pointer to the beginning of string being copied from. Must not overlap > + * dest. > + * > + * stpcpy differs from strcpy in two key ways: > + * 1. inputs must not overlap. > + * 2. return value is the new NULL terminated character. (for strcpy, the > + * return value is a pointer to src. > + */ > +#undef stpcpy > +char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) > +{ > + while ((*dest++ = *src++) != '\0') > + /* nothing */; > + return dest; > +} > +#endif > + Won't this return a pointer that's one _past_ the terminating NUL? I think you need the increments to be inside the loop body, rather than as part of the condition. Nit: NUL is more correct than NULL to refer to the string terminator.