diff options
Diffstat (limited to 'include/sqfs/data_writer.h')
| -rw-r--r-- | include/sqfs/data_writer.h | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/include/sqfs/data_writer.h b/include/sqfs/data_writer.h index 210a08d..4623493 100644 --- a/include/sqfs/data_writer.h +++ b/include/sqfs/data_writer.h @@ -59,6 +59,18 @@ */ struct sqfs_block_hooks_t { /** + * @brief Set this to the size of the struct. + * + * This is required for future expandabillity while maintaining ABI + * compatibillity. At the current time, the implementation of + * @ref sqfs_data_writer_set_hooks rejects any hook struct where this + * isn't the exact size. If new hooks are added in the future, the + * struct grows and the future implementation can tell by the size + * whether the application uses the new version or the old one. + */ + size_t size; + + /** * @brief Gets called before writing a block to disk. * * If this is not NULL, it gets called before a block is written to @@ -283,10 +295,13 @@ int sqfs_data_writer_write_fragment_table(sqfs_data_writer_t *proc, * @param proc A pointer to a data writer object. * @param user_ptr A user pointer to pass to the callbacks. * @param hooks A structure containing the hooks. + * + * @return Zero on success, @ref SQFS_ERROR_UNSUPPORTED if the size field of + * the hooks doesn't match any size knwon to the library. */ SQFS_API -void sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr, - const sqfs_block_hooks_t *hooks); +int sqfs_data_writer_set_hooks(sqfs_data_writer_t *proc, void *user_ptr, + const sqfs_block_hooks_t *hooks); #ifdef __cplusplus } |