ref: 72f9c4e49acb9d8d7397b6ea7de53ec9899a054c
dir: /sys/src/libString/s_terminate.c/
#include <u.h>
#include <libc.h>
#include "String.h"
void
s_terminate(String *s)
{
	if(s->ref > 1)
		sysfatal("can't s_terminate a shared string");
	if (s->ptr >= s->end)
		s_grow(s, 1);
	*s->ptr = 0;
}