cdds_lseek - seek position in DDS binary stream

SYNOPSIS

#include "cdds.h"

long cdds_lseek(bin , tag, offset, whence);

BIN_TAG bin
FIELD_TAG tag
long offset
int whence

[ Input | Output | Examples ]

DESCRIPTION

This function seeks a new position in a binary stream.

Pipe media only supports forward seeks.

INPUT

Bin is a binary tag, previously obtained from cdds_open. It specifies a particular binary stream.

tag is a field tag which specifies a tag associated with bin. This provides an offset relative to an absolute origin as defined by whence. If tag is zero (nominal), it defaults to the target (trace type) associated with bin.

Offset is a position, measured relative to the whence origin. The Offset should be an integral multiple of type relative to the absolute origin. Note that if bin was opened with the convenience routine cddx_in, offset will be in terms of traces. If bin was opened with the api routine cdds_in, offset will be in terms of bytes. 

whence     seek origin.
SEEK_SET   beginning of the file.
SEEK_CUR   current file position.
SEEK_END   end of the file.

OUTPUT

The current binary stream position may be changed.

The return value is the new offset, or -1 if an error occurred.

EXAMPLES

BIN_TAG bin;
...
/* Assuming bin was opened with cddx_in, skips next 10 target types (traces) */
cdds_lseek(bin, 0, 10, SEEK_CUR);

AUTHOR

R. L. Selzler, EPTG (Oct 1995)