2 files changed, 3 insertions, 3 deletions
diff --git a/src/stdlib/integers.c b/src/stdlib/integers.c
index b4ca69d3..bb39d99c 100644
--- a/src/stdlib/integers.c
+++ b/src/stdlib/integers.c
@@ -434,12 +434,12 @@ public Int_t Int$next_prime(Int_t x)
 
 #if __GNU_MP_VERSION >= 6
 #if __GNU_MP_VERSION_MINOR >= 3
-public Int_t Int$prev_prime(Int_t x)
+public OptionalInt_t Int$prev_prime(Int_t x)
 {
     mpz_t p;
     mpz_init_set_int(p, x);
     if (unlikely(mpz_prevprime(p, p) == 0))
-        fail("There is no prime number before ", x);
+        return NONE_INT;
     return Int$from_mpz(p);
 }
 #endif
diff --git a/src/stdlib/integers.h b/src/stdlib/integers.h
index c7643a8d..7b7cf12e 100644
--- a/src/stdlib/integers.h
+++ b/src/stdlib/integers.h
@@ -144,7 +144,7 @@ bool Int$is_prime(Int_t x, Int_t reps);
 Int_t Int$next_prime(Int_t x);
 #if __GNU_MP_VERSION >= 6
 #if __GNU_MP_VERSION_MINOR >= 3
-Int_t Int$prev_prime(Int_t x);
+OptionalInt_t Int$prev_prime(Int_t x);
 #endif
 #endif
 Int_t Int$choose(Int_t n, Int_t k);