ref: 37a8fc6168b3bf82df198fb20be5a8a53996187c
dir: /sys/src/libString/s_putc.c/
#include <u.h>
#include <libc.h>
#include "String.h"
void
s_putc(String *s, int c)
{
if(s->ref > 1)
sysfatal("can't s_putc a shared string");
if (s->ptr >= s->end)
s_grow(s, 2);
*(s->ptr)++ = c;
}