diff --git a/libm/fake_long_double.c b/libm/fake_long_double.c
index 815203389..9b934d2d5 100644
--- a/libm/fake_long_double.c
+++ b/libm/fake_long_double.c
@@ -52,6 +52,7 @@ long long llrintl(long double a1) { return llrint(a1); }
 long double log10l(long double a1) { return log10(a1); }
 long double log1pl(long double a1) { return log1p(a1); }
 long double log2l(long double a1) { return log2(a1); }
+long double logbl(long double a1) { return logb(a1); }
 long double logl(long double a1) { return log(a1); }
 long lrintl(long double a1) { return lrint(a1); }
 long long llroundl(long double a1) { return llround(a1); }