1 files changed, 1 insertions, 1 deletions
diff --git a/acosh.c b/acosh.c
index 92f31bf85..1e61f8ed6 100644
--- a/acosh.c
+++ b/acosh.c
@@ -121,7 +121,7 @@ mpfr_acosh (y, x, rnd_mode)
       /* actualisation of the precision */
       Nt += 10;
 
-    } while (!mpfr_can_round(t,err,GMP_RNDN,rnd_mode,Ny));
+    } while ((err<0) ||!mpfr_can_round(t,err,GMP_RNDN,rnd_mode,Ny));
  
     inexact = mpfr_set(y,t,rnd_mode);