From e8fc0bee2029371c213ea8e7d1e896671ddc72cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=BCtzel?= <markus.muetzel@gmx.de>
Date: Wed, 15 May 2024 19:00:37 +0200
Subject: [PATCH] Use `int64_t` for `KLU_INDEXTYPE` if `SUNDIALS_INT64_T` is
 defined.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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`long int` is 32 bits wide on systems that use an LLP64 data model
(e.g., Windows 64-bit). Use a type for which the C standard guarantees
that it is 64-bit instead (i.e., `int64_t`).

Signed-off-by: Markus Mützel <markus.muetzel@gmx.de>
---
 CHANGELOG.md                      | 3 +++
 doc/shared/RecentChanges.rst      | 3 +++
 src/sunlinsol/klu/sunlinsol_klu.c | 3 ++-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 59ffc7a35d..40706c1649 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -65,6 +65,9 @@ Fixed a CMake bug that caused an MPI linking error for our C++ examples in some
 Fixed a bug in `ARKodeSPRKTable_Create` where the coefficient arrays where not
 allocated.
 
+Fix bug on LLP64 platforms (like Windows 64-bit) where `KLU_INDEXTYPE` could be
+32 bits wide even if `SUNDIALS_INT64_T` is defined.
+
 ## Changes to SUNDIALS in release v7.0.0
 
 ### Major Feature
diff --git a/doc/shared/RecentChanges.rst b/doc/shared/RecentChanges.rst
index a6eef5064e..4f1e6dbe92 100644
--- a/doc/shared/RecentChanges.rst
+++ b/doc/shared/RecentChanges.rst
@@ -65,3 +65,6 @@ Fixed a CMake bug that caused an MPI linking error for our C++ examples in some
 
 Fixed a bug in :c:func:`ARKodeSPRKTable_Create` where the coefficient arrays
 where not allocated.
+
+Fix bug on LLP64 platforms (like Windows 64-bit) where ``KLU_INDEXTYPE`` could be
+32 bits wide even if ``SUNDIALS_INT64_T`` is defined.
diff --git a/src/sunlinsol/klu/sunlinsol_klu.c b/src/sunlinsol/klu/sunlinsol_klu.c
index cbdaa54135..568dc1d549 100644
--- a/src/sunlinsol/klu/sunlinsol_klu.c
+++ b/src/sunlinsol/klu/sunlinsol_klu.c
@@ -16,6 +16,7 @@
  * the SUNLINSOL package.
  * -----------------------------------------------------------------*/
 
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sundials/sundials_math.h>
@@ -49,7 +50,7 @@
  */
 
 #if defined(SUNDIALS_INT64_T)
-#define KLU_INDEXTYPE long int
+#define KLU_INDEXTYPE int64_t
 #else
 #define KLU_INDEXTYPE int
 #endif