.TH th_read 3 "Jan 2001" "University of Illinois" "C Library Calls"
.SH NAME
th_read, th_write \- read and write a file header block from a tar archive
.SH SYNOPSIS
.B #include <libtar.h>
.P
.BI "int th_read(TAR *" t ");"

.BI "int th_write(TAR *" t ");"
.SH VERSION
This man page documents version 1.2 of \fBlibtar\fP.
.SH DESCRIPTION
The \fBth_read\fP() function reads the next block from the tar archive
associated with the \fITAR\fP handle \fIt\fP.  It then sets the
current tar header associated with \fIt\fP to the contents of the block
read.

The \fBth_write\fP() function writes the contents of the current
tar header associated with \fIt\fP to the tar archive associated
with \fIt\fP.
.SH RETURN VALUE
On successful completion, \fBth_read\fP() and \fBth_write\fP() will
return 0.  On failure, they will return -1 and set \fIerrno\fP to an
appropriate value.

On \fIEOF\fP, \fBth_read\fP() will return 1.
.SH ERRORS
\fBth_read\fP() and \fBth_write\fP() will fail if:
.IP \fBEINVAL\fP
Less than \fBT_BLOCKSIZE\fP blocks were read or written.
.PP
.SH SEE ALSO
.BR tar_block_read (3),
.BR tar_block_write (3)