int
zip_file_extra_field_delete(struct zip *archive, zip_uint64_t index, zip_uint16_t extra_field_index, zip_flags_t flags);
int
zip_file_extra_field_delete_by_id(struct zip *archive, zip_uint64_t index, zip_uint16_t extra_field_id, zip_uint16_t extra_field_index, zip_flags_t flags);
If extra_field_index is ZIP_EXTRA_FIELD_ALL, then all extra fields will be deleted.
The following flags are supported:
The zip_file_extra_field_delete_by_id() function deletes 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_delete() (ZIP_EXTRA_FIELD_ALL will delete all extra fields of the specified ID).
Please note that due to the library design, the index of an extra field may be different between central directory and local file headers. For this reason, it is not allowed to specify both ZIP_FL_CENTRAL and ZIP_FL_LOCAL in flags, except when deleting all extra fields (i.e., extra_field_index being ZIP_EXTRA_FIELD_ALL).