.\" zip_file_extra_field_delete.mdoc -- delete extra field for file in zip
.\" Copyright (C) 2012-2013 Dieter Baron and Thomas Klausner
.\"
.\" This file is part of libzip, a library to manipulate ZIP files.
.\" The authors can be contacted at <libzip@nih.at>
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.Dd July 31, 2013
.Dt ZIP_FILE_EXTRA_FIELD_DELETE 3
.Os
.Sh NAME
.Nm zip_file_extra_field_delete ,
.Nm zip_file_extra_field_delete_by_id
.Nd delete extra field for file in zip
.Sh LIBRARY
libzip (-lzip)
.Sh SYNOPSIS
.In zip.h
.Ft int
.Fn zip_file_extra_field_delete "struct zip *archive" "zip_uint64_t index" \
"zip_uint16_t extra_field_index" "zip_flags_t flags"
.Ft int
.Fn zip_file_extra_field_delete_by_id "struct zip *archive" "zip_uint64_t index" \
"zip_uint16_t extra_field_id" "zip_uint16_t extra_field_index" "zip_flags_t flags"
.Sh DESCRIPTION
The
.Fn zip_file_extra_field_delete
function deletes the extra field with index
.Ar extra_field_index
for the file at position
.Ar index
in the zip archive.
.Pp
If
.Ar extra_field_index
is
.Dv ZIP_EXTRA_FIELD_ALL ,
then all extra fields will be deleted.
.Pp
The following
.Ar flags
are supported:
.Bl -tag -width ZIP_FL_CENTRALXX -offset indent
.It Dv ZIP_FL_CENTRAL
Delete extra fields from the archive's central directory.
.It Dv ZIP_FL_LOCAL
Delete extra fields from the local file headers.
.El
.Pp
The
.Fn zip_file_extra_field_delete_by_id
function deletes the extra field with ID (two-byte signature)
.Ar extra_field_id
and index
.Ar extra_field_index
(in other words, the
.Ar extra_field_index Ns No 'th
extra field with ID
.Ar extra_field_id )
The other arguments are the same as for
.Fn zip_file_extra_field_delete
.Dv ( ZIP_EXTRA_FIELD_ALL
will delete all extra fields of the specified ID).
.Pp
Please note that due to the library design, the index of an extra
field may be different between central directory and local file
headers.
For this reason, it is not allowed to specify both
.Dv ZIP_FL_CENTRAL
and
.Dv ZIP_FL_LOCAL
in
.Ar flags ,
except when deleting all extra fields (i.e.,
.Ar extra_field_index
being
.Dv ZIP_EXTRA_FIELD_ALL ) .
.Sh RETURN VALUES
Upon successful completion 0 is returned.
Otherwise, \-1 is returned and the error code in
.Ar archive
is set to indicate the error.
.Sh ERRORS
.Fn zip_file_extra_field_delete
and
.Fn zip_file_extra_field_delete_by_id
fail if:
.Bl -tag -width Er
.It Bq Er ZIP_ER_NOENT
.Ar index
is not a valid file index in
.Ar archive .
.El
.Sh SEE ALSO
.Xr libzip 3 ,
.Xr zip_file_extra_field_get 3 ,
.Xr zip_file_extra_field_set 3 ,
.Xr zip_file_extra_fields_count 3
.Sh AUTHORS
.An -nosplit
.An Dieter Baron Aq Mt dillo@nih.at
and
.An Thomas Klausner Aq Mt tk@giga.or.at