ext3 code understanding

Question

struct inode_operations ext3_dir_inode_operations = {
        .create         = ext3_create,
        .lookup         = ext3_lookup,
}

This struct is assign to inode structure and further to file system operation structure. My question is what is this flag .create? Do we do the assignment in the structure itself? Or is it some other version of C (C99, C89?) that allows this kind of operation?

I hope my question is clear.

Answer 1

It's a C99 designated initialiser. It's equivalent to, in C89:

struct inode_operations ext3_dir_inode_operations = { 0 };
ext3_dir_inode_operations.create = ext3_create;
ext3_dir_inode_operations.lookup = ext3_lookup;