Proper startup in order to get best list of aps with scan_results

Jouni Malinen jkmaline at
Sun Sep 10 19:21:23 EDT 2006

On Wed, Sep 06, 2006 at 04:51:39PM -0700, George S. Lockwood wrote:

> How to get the best scan_results at cli startup?  Should I ap_scan=1
> and then enable a "dummy" network? then scan_results?  I don't wish to
> connect at startup, just get a list of aps.  Connecting to a network
> happens a bit later.

You do not need to add a network for this to work. Just start
wpa_supplicant with an empty configuration file in either ap_scan=1 or
ap_scan=2 mode and issue SCAN command. Then wait seven seconds (timeout
for scan results to be read and if I remember correctly, the interval
after which NDIS drivers are required to have scan results ready) and
issue SCAN_RESULTS to read the results.

> the other question I have about scanning is in that other thread, but
> is: do I request a scan, and then wait for some precribed amount of
> time (to wait for the NIC to finish scanning), and then request a
> scan_result? or can I call scan_result immediately after a scan
> request (because control won't return to me until the scan has
> completed)?

You will need to wait for this since SCAN commands is not blocking. You
can use SCAN_RESULTS without a wait, but there is no guarantee that the
results are up-to-date or event available at that point unless you wait
long enough (seven seconds in case of NDIS drivers).

Jouni Malinen                                            PGP id EFC895FA

More information about the HostAP mailing list