From ac3a02b80bf78c4212eab930243c1a2e0ca9c728 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Fri, 21 Mar 2025 16:19:59 -0400
Subject: [PATCH] Add version check for GNU MP's prev_prime()

---
 environment.c     | 4 ++++
 stdlib/integers.c | 4 ++++
 stdlib/integers.h | 4 ++++
 test/integers.tm  | 4 ++--
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/environment.c b/environment.c
index 7b4bb5b..9f230cd 100644
--- a/environment.c
+++ b/environment.c
@@ -120,7 +120,11 @@ env_t *global_env(void)
             {"parse", "Int$parse", "func(text:Text -> Int?)"},
             {"plus", "Int$plus", "func(x,y:Int -> Int)"},
             {"power", "Int$power", "func(base:Int,exponent:Int -> Int)"},
+#if __GNU_MP_VERSION >= 6
+#if __GNU_MP_VERSION_MINOR >= 3
             {"prev_prime", "Int$prev_prime", "func(x:Int -> Int)"},
+#endif
+#endif
             {"right_shifted", "Int$right_shifted", "func(x,y:Int -> Int)"},
             {"sqrt", "Int$sqrt", "func(x:Int -> Int?)"},
             {"times", "Int$times", "func(x,y:Int -> Int)"},
diff --git a/stdlib/integers.c b/stdlib/integers.c
index c4fcdfb..4d5d0a8 100644
--- a/stdlib/integers.c
+++ b/stdlib/integers.c
@@ -409,6 +409,8 @@ public Int_t Int$next_prime(Int_t x)
     return Int$from_mpz(p);
 }
 
+#if __GNU_MP_VERSION >= 6
+#if __GNU_MP_VERSION_MINOR >= 3
 public Int_t Int$prev_prime(Int_t x)
 {
     mpz_t p;
@@ -417,6 +419,8 @@ public Int_t Int$prev_prime(Int_t x)
         fail("There is no prime number before %k", (Text_t[1]){Int$as_text(&x, false, &Int$info)});
     return Int$from_mpz(p);
 }
+#endif
+#endif
 
 public Int_t Int$choose(Int_t n, Int_t k)
 {
diff --git a/stdlib/integers.h b/stdlib/integers.h
index 3bc3abe..e058688 100644
--- a/stdlib/integers.h
+++ b/stdlib/integers.h
@@ -142,7 +142,11 @@ Int_t Int$slow_negative(Int_t x);
 Int_t Int$slow_negated(Int_t x);
 bool Int$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);
+#endif
+#endif
 Int_t Int$choose(Int_t n, Int_t k);
 Int_t Int$factorial(Int_t n);
 
diff --git a/test/integers.tm b/test/integers.tm
index e6b2ba9..9ab0b0c 100644
--- a/test/integers.tm
+++ b/test/integers.tm
@@ -96,8 +96,8 @@ func main():
 	= 2
 	>> 7:next_prime()
 	= 11
-	>> 11:prev_prime()
-	= 7
+	#>> 11:prev_prime()
+	#= 7
 	>> (and: p:is_prime() for p in [
 		2, 3, 5, 7,
 		137372146048179869781170214707,