This routine replaces a character in a <A HREF="strbuf.html">String_buf</A>.
If the index i is out of range, nothing happens.
<A NAME="sb_size"></A><HR><PRE><B>int sb_size(<A HREF="strbuf.html">String_buf</A> sb);
</B></PRE><A NAME="sb_to_malloc_char_array"></A><HR><PRE><B>char *sb_to_malloc_char_array(<A HREF="strbuf.html">String_buf</A> sb);
</B></PRE>This routine is similar to <A HREF="#sb_to_malloc_string">sb_to_malloc_string</A>(), except that
null characters are copied to the new string. 
<A NAME="sb_