Conky: 'if_match ${wireless_link_qual_perc' fails occasionally

    'if_match ${wireless_link_qual_perc' fails occasionally - I think when the network is coming up. To be more specific about the problem (as against when it occurs):

${if_match ${wireless_link_qual_perc wlan0}>70}\

returns an error to the effect that wireless_link_qual_perc wlan0 is a string (!); and the condition seems to get evaluated as false. (Though I'll have to wait until the next time the situation occurs to be sure.)

    A related problem is that, when the foregoing situation occurs - i.e. wireless_link_qual_perc gets the wrong type of value - the following condition is satisfied:

${if_up wlan0}\

I have if_up_strictness set to "address".

    To sum up / clarify - my Conky contains (among other code) the following.

${if_up wlan0}\
# WLAN 0
${if_match ${wireless_link_qual_perc wlan0}>70}\

The first line evaluates as true when, it seems, the network has not finished coming up; and when that situation obtains, the third line throws an error.

    'All of this makes my Conky behaviour a bit erratic and I've had to build in checks to work around the problems.

Conky 1.10.6-1. Linux Mint 18.2 x64.