From 21f54c53b96c7a70ec2a0b4472578c7c70838ee2 Mon Sep 17 00:00:00 2001
From: Jürgen Knödlseder <jurgen.knodlseder@irap.omp.eu>
Date: Fri, 28 May 2021 12:45:14 +0200
Subject: [PATCH] Autodetect RTLD_GLOBAL and RTLD_NOW values and use those in __init__.py.in (#35)

---
 configure.ac                  | 17 +++++++----------
 m4/ax_dlflags.m4              | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 pyext/gammalib/__init__.py.in |  9 +++++----
 3 files changed, 64 insertions(+), 14 deletions(-)
 create mode 100644 m4/ax_dlflags.m4

diff --git a/configure.ac b/configure.ac
index db381be..3e0cede 100644
--- a/configure.ac
+++ b/configure.ac
@@ -289,21 +289,17 @@ AC_MSG_CHECKING([for the shared library paths environment variable])
 case $ac_sys_system in
     BeOS*)
         SHAREDSUFFIX='.so'
-        DLFLAGS=258
         ;;
     CYGWIN*)
         SHAREDSUFFIX='.dll.a'
-        DLFLAGS=258
         ;;
     SunOS*)
         SHAREDSUFFIX='.so'
         RUNSHARED='LD_LIBRARY_PATH'
-        DLFLAGS=258
         ;;
     Linux*|GNU*|NetBSD*|FreeBSD*|DragonFly*)
         SHAREDSUFFIX='.so'
         RUNSHARED='LD_LIBRARY_PATH'
-        DLFLAGS=258
         ;;
     hp*|HP*)
         case `uname -m` in
@@ -315,33 +311,34 @@ case $ac_sys_system in
                 ;;
         esac
         RUNSHARED='SHLIB_PATH'
-        DLFLAGS=258
         ;;
     OSF*)
         SHAREDSUFFIX='.so'
         RUNSHARED='LD_LIBRARY_PATH'
-        DLFLAGS=258
         ;;
     atheos*)
         SHAREDSUFFIX='.so'
         RUNSHARED='DLL_PATH'
-        DLFLAGS=258
 	    ;;
     Darwin*)
         SHAREDSUFFIX='.dylib'
         RUNSHARED='DYLD_LIBRARY_PATH'
-        DLFLAGS=10
         ;;
     AIX*)
         SHAREDSUFFIX='.so'
         RUNSHARED='LIBPATH'
-        DLFLAGS=258
         ;;
 esac
 AC_MSG_RESULT($RUNSHARED)
 AC_SUBST(SHAREDSUFFIX)
 AC_SUBST(RUNSHARED)
-AC_SUBST(DLFLAGS)
+
+
+#############################################################################
+# Determine values of RTLD_GLOBAL and RTLD_NOW                              #
+#############################################################################
+AX_DLFLAGS(RTLD_GLOBAL)
+AX_DLFLAGS(RTLD_NOW)
 
 
 #############################################################################
diff --git a/m4/ax_dlflags.m4 b/m4/ax_dlflags.m4
new file mode 100644
index 0000000..2c7df59
--- /dev/null
+++ b/m4/ax_dlflags.m4
@@ -0,0 +1,52 @@
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_DLFLAGS
+#
+# DESCRIPTION
+#
+#   This macro determines the value of a DL flags such as RTLD_GLOBAL or
+#   RTLD_NOW from the dlfcn.h file.
+#
+# USAGE
+#
+#   AX_DLFLAGS(RTLD_GLOBAL)
+#   AC_MSG_RESULT($DLFLAGS_RTLD_GLOBAL)
+#
+# LICENSE
+#
+#   Copyright (c) 2021 Juergen Knodlseder
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#serial 8
+
+AC_DEFUN([AX_DLFLAGS], [
+  DLFLAGS_$1=""
+  AC_CHECK_HEADERS([dlfcn.h])
+  AS_IF([test "x$ac_cv_header_dlfcn_h" = "xyes"],[
+    AC_MSG_CHECKING([for value of $1])
+    for flags in 1 2 4 8 16 32 64 128 256 512 ; do
+      AC_EGREP_CPP([test_true],[
+        #include <dlfcn.h>
+        #if defined($1) && $1 == $flags
+        test_true
+        #endif
+        ],[DLFLAGS_$1=$flags],[])
+    done
+    ])
+  AC_MSG_RESULT($DLFLAGS_$1)
+  AC_SUBST([DLFLAGS_$1])
+])
diff --git a/pyext/gammalib/__init__.py.in b/pyext/gammalib/__init__.py.in
index efd668a..d63d266 100644
--- a/pyext/gammalib/__init__.py.in
+++ b/pyext/gammalib/__init__.py.in
@@ -18,11 +18,12 @@
 #
 # ==========================================================================
 
-# Make sur that library symbols are exported by setting the RTLD_GLOBAL flag.
-# This is necessary on some systems.
+# Make sur that library symbols are exported by setting the dynamic library
+# loading flag to RTLD_GLOBAL | RTLD_NOWflag. This is necessary on some
+# systems.
 import sys
-flags = sys.getdlopenflags()  # Get original flags
-sys.setdlopenflags(@DLFLAGS@) # Set RTLD_GLOBAL | RTLD_NOW
+flags = sys.getdlopenflags()
+sys.setdlopenflags(@DLFLAGS_RTLD_GLOBAL@ | @DLFLAGS_RTLD_NOW@)
 
 # Import modules
 from gammalib.app import *
--
libgit2 0.21.4