int mdb_walk(const char *name, mdb_walk_cb_t func, void *data);
Initiate a global walk starting at addr using the walker specified by name, and invoke the callback function func at each step. This function returns 0 for success, or -1 for error. The mdb_walk() function fails if the walker itself returns a fatal error, or if the specified walker name is not known to the debugger. The walker name can be scoped using the backquote (`) operator if there are naming conflicts. The data parameter is an opaque argument that has meaning only to the caller; it is passed back to func at each step of the walk.