From 1a3d36fdbfbfc274c1d26b0e8e85c5e08fcb3cb6 Mon Sep 17 00:00:00 2001
From: Richard Berger <rberger@lanl.gov>
Date: Fri, 8 Dec 2023 23:59:41 -0700
Subject: [PATCH] Use PyConfig to initialize Python

---
 src/PYTHON/python_impl.cpp | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/PYTHON/python_impl.cpp b/src/PYTHON/python_impl.cpp
index 57f8ea1cf0..6dd5175621 100644
--- a/src/PYTHON/python_impl.cpp
+++ b/src/PYTHON/python_impl.cpp
@@ -61,16 +61,19 @@ PythonImpl::PythonImpl(LAMMPS *lmp) : Pointers(lmp)
   nfunc = 0;
   pfuncs = nullptr;
 
-#if PY_MAJOR_VERSION >= 3
-#ifndef Py_LIMITED_API
+#if PY_MAJOR_VERSION >= 3 && !defined(Py_LIMITED_API)
   // check for PYTHONUNBUFFERED environment variable
   const char *PYTHONUNBUFFERED = getenv("PYTHONUNBUFFERED");
+  // Force the stdout and stderr streams to be unbuffered.
+  bool unbuffered = PYTHONUNBUFFERED != nullptr && strcmp(PYTHONUNBUFFERED, "1") == 0;
 
-  if (PYTHONUNBUFFERED != nullptr && strcmp(PYTHONUNBUFFERED, "1") == 0) {
-    // Python Global configuration variable
-    // Force the stdout and stderr streams to be unbuffered.
-    Py_UnbufferedStdioFlag = 1;
-  }
+#if PY_VERSION_HEX >= 0x030800f0
+  PyConfig config;
+  PyConfig_InitPythonConfig(&config);
+  config.buffered_stdio = !unbuffered;
+#else
+  // Python Global configuration variable
+  Py_UnbufferedStdioFlag = unbuffered;
 #endif
 #endif
 
@@ -94,12 +97,17 @@ PythonImpl::PythonImpl(LAMMPS *lmp) : Pointers(lmp)
 #endif
 #endif
 
+#if PY_VERSION_HEX >= 0x030800f0 && !defined(Py_LIMITED_API)
+  Py_InitializeFromConfig(&config);
+  PyConfig_Clear(&config);
+#else
   Py_Initialize();
+#endif
 
   // only needed for Python 2.x and Python 3 < 3.7
   // With Python 3.7 this function is now called by Py_Initialize()
   // Deprecated since version 3.9, will be removed in version 3.11
-#if PY_MAJOR_VERSION < 3 || PY_MINOR_VERSION < 7
+#if PY_VERSION_HEX < 0x030700f0
   if (!PyEval_ThreadsInitialized()) { PyEval_InitThreads(); }
 #endif