ZIP_FILE_EXTRA_FIELD_SET(3) Library Functions Manual ZIP_FILE_EXTRA_FIELD_SET(3)

zip_file_extra_field_set —
set extra field for file in zip

libzip (-lzip)

#include <zip.h>

int
zip_file_extra_field_set(zip_t *archive, zip_uint64_t index, zip_uint16_t extra_field_id, zip_uint16_t extra_field_index, const zip_uint8_t *extra_field_data, zip_uint16_t len, zip_flags_t flags);

The zip_file_extra_field_set() function sets the extra field with ID (two-byte signature) extra_field_id and index extra_field_index for the file at position index in the zip archive. The extra field's data will be set to extra_field_data and length len. If a new entry shall be appended, set extra_field_index to ZIP_EXTRA_FIELD_NEW.

At least one of the following flags must be set:

Set extra field in the archive's central directory.
Set extra field in the local file headers.

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 set using zip_file_extra_field_set() since they are set by libzip(3) automatically when needed.

Upon successful completion 0 is returned. Otherwise, -1 is returned and the error code in archive is set to indicate the error.

zip_file_extra_field_set() fails if:
[]
The extra field size is too large (ID and length need 4 bytes; the maximum length of all extra fields for one file combined is 65536 bytes). This error also occurs if extra_field_index is too large.
[]
Required memory could not be allocated.
[]
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_fields_count(3)

zip_file_extra_field_set() was added in libzip 0.11.

Dieter Baron <dillo@nih.at> and Thomas Klausner <tk@giga.or.at>
December 18, 2017 NiH