stdiom.h

操作系统SunOS 4.1.3版本的源码

/*	@(#)stdiom.h 1.1 92/07/30 SMI; from S5R2 1.1	*/

/* The following macros improve performance of the stdio by reducing the
	number of calls to _bufsync and _wrtchk.  _BUFSYNC has the same
	effect as _bufsync, and _WRTCHK has the same effect as _wrtchk,
	but often these functions have no effect, and in those cases the
	macros avoid the expense of calling the functions.  */

#define _BUFSYNC(iop)	if ((iop->_base + iop->_bufsiz) - iop->_ptr <   \
				( iop->_cnt < 0 ? 0 : iop->_cnt ) )  \
					_bufsync(iop)
#define _WRTCHK(iop)	((((iop->_flag & (_IOWRT | _IOEOF)) != _IOWRT) \
				|| (iop->_base == NULL)  \
				|| (iop->_ptr == iop->_base && iop->_cnt == 0 \
					&& !(iop->_flag & (_IONBF | _IOLBF)))) \
			? _wrtchk(iop) : 0 )