man/zip_file_extra_field_get.man

.\" zip_file_extra_field_get.mdoc \-- get extra field for file in zip
.\" Copyright (C) 2012 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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.TH ZIP_FILE_EXTRA_FIELD_GET 3 "June 23, 2012" NiH
.SH "NAME"
zip_file_extra_field_get , \- .Nm zip_file_extra_field_get_by_id
get extra field for file in zip
.SH "LIBRARY"
libzip (-lzip)
.SH "SYNOPSIS"
#include <zip.h>
.PP
const zip_uint8_t *
zip_file_extra_field_get(struct zip *archive, zip_uint64_t index); \
"zip_uint16_t extra_field_index" "zip_uint16_t *idp" "zip_uint16_t *lenp" \
"zip_flags_t flags"
.PP
const zip_uint8_t *
zip_file_extra_field_get_by_id(struct zip *archive, zip_uint64_t index); \
"zip_uint16_t extra_field_id" "zip_uint16_t extra_field_index" "zip_uint16_t *lenp" \
"zip_flags_t flags"
.SH "DESCRIPTION"
The
zip_file_extra_field_get
function returns the extra field with index
\fBextra_field_index\fR
for the file at position
\fBindex\fR
in the zip archive.
This pointer should not be modified or
free(3)
Ap d,
and becomes invalid when
\fBarchive\fR
is closed.
If
\fBidp\fR
is not
\fBNULL,\fR
the integer to which it points will be set to the ID (two-byte
signature) of the selected extra field.
If
\fBlenp\fR
is not
\fBNULL,\fR
the integer to which it points will be set to the length of the
extra field.
Generally speaking,
\fBlenp\fR
and
\fBidp\fR
should be passed since only the extra field data is returned (i.e.,
neither the ID nor the length, if the
\fBidp\fR
and
\fBlenp\fR
arguments are not provided).
.PP
The following flags are supported:
.RS
.TP 18
\fBZIP_FL_CENTRAL\fR
Return only extra fields from the archive's central directory.
.TP 18
\fBZIP_FL_LOCAL\fR
Return only extra fields from the local file headers.
.TP 18
\fBZIP_FL_UNCHANGED\fR
Return only the original unchanged extra fields.
.RE
.PP
The
zip_file_extra_field_get_by_id
function returns the extra field with ID (two-byte signature)
\fBextra_field_id\fR
and index
\fBextra_field_index\fR
(in other words, the
\fBextra_field_index'th\fR
extra field with ID
\fBextra_field_id )\fR
The other arguments are the same as for
zip_file_extra_field_get.
.SH "RETURN VALUES"
Upon successful completion, a pointer to an extra field is returned,
or
\fBNULL\fR
if there is no extra field with that
\fBextra_field_index\fR
for the file with index
\fBindex.\fR
In case of an error,
\fBNULL\fR
is returned and the error code in
\fBarchive\fR
is set to indicate the error.
.SH "ERRORS"
zip_file_extra_field_get
and
zip_file_extra_field_get_by_id
fail if:
.RS
.TP 4
[ZIP_ER_NOENT]
\fBindex\fR
is not a valid file index in
\fBarchive,\fR
or
\fBextra_field_index\fR
is not a valid extra file index (for ID
\fBextra_field_id ).\fR
.RE
.SH "SEE ALSO"
libzip(3),
zip_file_extra_field_delete(3),
zip_file_extra_field_set(3),
zip_file_extra_fields_count(3)
.SH "AUTHORS"

Dieter Baron <dillo@giga.or.at>
and
Thomas Klausner <tk@giga.or.at>