Tribblix: manual page: zip_file_extra_field

ZIP_FILE_EXTRA_FIELD_GET(3) Introduction to Library Functions

NAME

zip_file_extra_field_get, zip_file_extra_field_get_by_id - get extra
field for file in zip

LIBRARY

libzip (-lzip)

SYNOPSIS

#include <zip.h>

const zip_uint8_t *
zip_file_extra_field_get(zip_t *archive, zip_uint64_t index,
zip_uint16_t extra_field_index, zip_uint16_t *idp,
zip_uint16_t *lenp, zip_flags_t flags);

const zip_uint8_t *
zip_file_extra_field_get_by_id(zip_t *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);

DESCRIPTION

The zip_file_extra_field_get() function returns the extra field with
index extra_field_index for the file at position index in the zip
archive. This pointer should not be modified or free(3)'d, and becomes
invalid when archive is closed. If idp is not NULL, the integer to
which it points will be set to the ID (two-byte signature) of the
selected extra field. If lenp is not NULL, the integer to which it
points will be set to the length of the extra field. Generally
speaking, lenp and idp should be passed since only the extra field data
is returned (i.e., neither the ID nor the length, if the idp and lenp
arguments are not provided).

The following flags are supported:

ZIP_FL_CENTRAL Return extra fields from the archive's
central directory.

ZIP_FL_LOCAL Return extra fields from the local file
headers.

ZIP_FL_UNCHANGED Return the original unchanged extra fields,
ignoring any changes made.

The zip_file_extra_field_get_by_id() function returns the extra field
with ID (two-byte signature) extra_field_id and index extra_field_index
(in other words, the extra_field_index'th extra field with ID
extra_field_id) The other arguments are the same as for
zip_file_extra_field_get().

RETURN VALUES

Upon successful completion, a pointer to an extra field is returned, or
NULL if there is no extra field with that extra_field_index for the
file with index index. In case of an error, NULL is returned and the
error code in archive is set to indicate the error.

ERRORS

zip_file_extra_field_get() and zip_file_extra_field_get_by_id() fail
if:

[ZIP_ER_NOENT] index is not a valid file index in archive, or
extra_field_index is not a valid extra file index
(for ID extra_field_id).

HISTORY

zip_file_extra_field_get() and zip_file_extra_field_get_by_id() were
added in libzip 0.11.

AUTHORS

Dieter Baron <dillo@nih.at> and Thomas Klausner <wiz@gatalith.at>

CAVEATS

Please note that the extra field IDs 0x0001 (ZIP64 extension), 0x6375
(Infozip UTF-8 comment), and 0x7075 (Infozip UTF-8 file name) can not
be read using zip_file_extra_field_get() since they are used by
libzip(3) internally.

illumos December 18, 2017 illumos