Bird's internal sprintf doesn't support floats, at least for now, in 1.6.x probably forever. There may be some patch that adds it. Look for some branch with "flowspec", I think I was implementing something like this for printing BGP flowspec and it is probably not merged. I don't have the git here now, maybe I can find it tomorrow. Maria Quidquid latine dictum sit, altum videtur. -----Original Message----- From: Mattia Milani <mattia.milani@studenti.unitn.it> To: BIRD Users <bird-users@network.cz> Sent: Fri, 30 Mar 2018 6:32 PM Subject: Can't Log information about a double Hello all, I'm trying to log some information during the bird process execution. I'm doing it in the bgp section. I used the command: log(L_INFO "** some text **"); with success, i added to the log some information about an integer variable with success, here it is the code: int a = 5; log(L_INFO "** some text ** %d", a); Now i'm trying to make the same with a double variable but without success double a = 5.5; log(L_INFO "** some text ** %lf", a); the output was: 2018-03-30 18:09:12.270 <INFO> ** some text ** %f I had already tried with %f instead of %lf but nothing changed in the output How can i log some double value? i need to use another function instead of log()? Thanks, Mattia