read_r.c

来自「FAT16 Filesystem on Philips LPC2000 seri」· C语言 代码 · 共 25 行

#include <reent.h>
#include <errno.h>
#include <devices.h>
#include <sysdefs.h>
#include <iface.h>

_ssize_t _read_r ( struct _reent *ptr, int fd, _PTR buf, size_t cnt)
{
#ifdef HAS_MMC
int	idx;
		// zero read always returns 0.
	if (cnt == 0) return cnt;
		// look thru device table for this device.
	if ((idx = find_device (ptr, DEVICE_TYPE(fd))) == -1) return -1;
		// call function if defined.
	if (device_table_list [idx].item->read) {
		return device_table_list [idx].item->read(ptr, fd, buf, cnt);
	}
#endif
	ptr->_errno = EBADF;
	return -1;
}