'\" t
.\"     Title: afSeekFrame
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
.\"      Date: 03/06/2013
.\"    Manual: \ \&
.\"    Source: Audio File Library 0.3.6
.\"  Language: English
.\"
.TH "AFSEEKFRAME" "3" "03/06/2013" "Audio File Library 0\&.3\&.6" "\ \&"
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.SH "NAME"
afSeekFrame, afTellFrame \- update or access the current sample frame position for a track in an audio file
.SH "SYNOPSIS"
.sp
.nf
#include <audiofile\&.h>
.fi
.sp
.nf
AFframecount afSeekFrame(AFfilehandle file, int track,
    AFframecount frameOffset);
.fi
.sp
.nf
AFframecount afTellFrame(AFfilehandle file, int track);
.fi
.SH "PARAMETERS"
.sp
\fIfile\fR is a valid audio file handle created by \fBafOpenFile\fR(3)\&.
.sp
\fItrack\fR identifies an audio track within the file\&. track is always AF_DEFAULT_TRACK for all currently supported audio file formats\&.
.sp
\fIframeOffset\fR is a sample frame offset\&. Valid sample frame offsets must be greater than or equal to zero and strictly less than the number of sample frames contained within the specified audio track\&. The special value \-1 is also allowed\&.
.SH "DESCRIPTION"
.sp
afSeekFrame moves the logical file position for a specified audio track to a desired sample frame location\&. If frameOffset is \-1, afSeekFrame will not modify the current file offset and will instead return the current file position\&.
.sp
afTellFrame returns current file position in sample frames\&.
.SH "RETURN VALUE"
.sp
On success, afSeekFrame and afTellFrame will return the current file position as measured in sample frames from the start of the audio track\&. On failure, afSeekFrame and afTellFrame will return the value \-1\&.
.SH "ERRORS"
.sp
The following errors can be generated by afSeekFrame or afTellFrame:
.PP
AF_BAD_FILEHANDLE
.RS 4

file
does not represent a valid file handle\&.
.RE
.PP
AF_BAD_TRACK
.RS 4

track
does not identify a valid track\&.
.RE
.PP
AF_BAD_LSEEK
.RS 4
A call to
lseek
failed\&.
.RE
.SH "AUTHOR"
.sp
Michael Pruett <michael@68k\&.org>