#include "stdio.h" ungetc(c, iop) register struct _iobuf *iop; { if ((iop->_flag&_IOREAD)==0 || iop->_ptr <= iop->_base) if (iop->_ptr == iop->_base && iop->_cnt==0) *iop->_ptr++; else _error("ungetc\n"); iop->_cnt++; *--iop->_ptr = c; }