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).

SEE ALSO

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

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 <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.

Debian                                          December 18, 2017                    ZIP_FILE_EXTRA_FIELD_GET(3)