zip_file_extra_fields_count, zip_file_extra_fields_count_by_id
count extra fields for file in zip

libzip (-lzip)

#include <zip.h>

zip_file_extra_fields_count(zip_t *archive, zip_uint64_t index, zip_flags_t flags);

zip_file_extra_fields_count_by_id(zip_t *archive, zip_uint64_t index, zip_uint16_t extra_field_id, zip_flags_t flags);

The zip_file_extra_fields_count() function counts the extra fields for the file at position index in the zip archive.

The following flags are supported:

Count extra fields from the archive's central directory.
Count extra fields from the local file headers.
Count the original unchanged extra fields, ignoring any changes made.

The zip_file_extra_fields_count_by_id() function counts the extra fields with ID (two-byte signature) extra_field_id. The other arguments are the same as for zip_file_extra_fields_count().

Extra fields that are the same in the central directory and the local file header are merged into one. Therefore, the counts with ZIP_FL_CENTRAL and ZIP_FL_LOCAL do not need to add up to the same value as when given ZIP_FL_CENTRAL|ZIP_FL_LOCAL at the same time.

Upon successful completion, the requested number of extra fields is returned. Otherwise, -1 is returned and the error code in archive is set to indicate the error.

zip_file_extra_fields_count() and zip_file_extra_fields_count_by_id() fail if:
index is not a valid file index in archive.

libzip(3), zip_file_extra_field_delete(3), zip_file_extra_field_get(3), zip_file_extra_field_set(3)

zip_file_extra_fields_count() and zip_file_extra_fields_count_by_id() were added in libzip 0.11.

Dieter Baron <> and Thomas Klausner <>