ctl_getopt_func

Declaration

typedef errno_t (*ctl_getopt_func)(kern_ctl_ref kctlref, u_int32_t unit, void *unitinfo, int opt, void *data, size_t *len);

Parameters

• kctlref:

  The control ref of the kernel control.

• unit:

  The unit number of the kernel control instance.

• unitinfo:

  The user-defined private data initialized by the ctl_connect_func callback.

• opt:

  The socket option.

• data:

  A buffer to copy the results in to. May be NULL, see discussion.

• len:

  A pointer to the length of the buffer. This should be set to the length of the buffer used before returning.

Discussion

The ctl_getopt_func is used to handle client get socket option requests for the SYSPROTO_CONTROL option level. A buffer is allocated for storage and passed to your function. The length of that buffer is also passed. Upon return, you should set *len to length of the buffer used. In some cases, data may be NULL. When this happens, *len should be set to the length you would have returned had data not been NULL. If the buffer is too small, return an error.