diff --git a/src/ttltrack.c b/src/ttltrack.c
index acac061..0fda582 100644
--- a/src/ttltrack.c
+++ b/src/ttltrack.c
@@ -241,7 +241,7 @@ int tcp_get_auto_ttl(const uint8_t ttl, const uint8_t autottl1,
 
     ttl_of_fake_packet = nhops - autottl2;
     if (ttl_of_fake_packet < autottl2 && nhops <= 9) {
-        ttl_of_fake_packet = nhops - autottl1 - trunc((autottl2 - autottl1) * ((float)nhops/10));
+        ttl_of_fake_packet = nhops - autottl1 - truncf((autottl2 - autottl1) * ((float)nhops/10));
     }
 
     if (maxttl && ttl_of_fake_packet > maxttl) {
@@ -249,4 +249,4 @@ int tcp_get_auto_ttl(const uint8_t ttl, const uint8_t autottl1,
     }
 
     return ttl_of_fake_packet;
-}
\ No newline at end of file
+}