Initial revision

lib/stdio/fseek.c

@@ -0,0 +1,44 @@
+/*
+ * fseek.c - perform an fseek
+ */
+/* $Header$ */
+
+#include	<stdio.h>
+
+#if	(SEEK_CUR != 1) || (SEEK_END != 2) || (SEEK_SET != 0)
+#error SEEK_* values are wrong
+#endif
+
+#include	"loc_incl.h"
+
+#include	<sys/types.h>
+
+off_t _lseek(int fildes, off_t offset, int whence);
+
+int
+fseek(FILE *stream, long int offset, int whence)
+{
+	int adjust = 0;
+	long pos;
+
+	stream->_flags &= ~(_IOEOF | _IOERR);
+	/* Clear both the end of file and error flags */
+
+	if (io_testflag(stream, _IOREADING)) {
+		if (whence == SEEK_CUR
+		    && stream->_buf
+		    && !io_testflag(stream,_IONBF))
+			adjust = stream->_count;
+		stream->_count = 0;
+	} else if (io_testflag(stream,_IOWRITING)) {
+		fflush(stream);
+	} else	/* neither reading nor writing. The buffer must be empty */
+		/* EMPTY */ ;
+
+	pos = _lseek(fileno(stream), offset - adjust, whence);
+	if (io_testflag(stream, _IOREAD) && io_testflag(stream, _IOWRITE))
+		stream->_flags &= ~(_IOREADING | _IOWRITING);
+
+	stream->_ptr = stream->_buf;
+	return ((pos == -1) ? -1 : 0);
+}