NAME

       zip_file_extra_field_get, zip_file_extra_field_get_by_id - get extra field for file in zip

LIBRARY

       libzip (-lzip)

SYNOPSIS

       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).

SEE ALSO

       libzip(3),          zip_file_extra_field_delete(3),           zip_file_extra_field_set(3),
       zip_file_extra_fields_count(3)

AUTHORS

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