From: Luca Boccassi <[email protected]>
Detect the SONAME at build time, and provide it as a variable for
programs to use, to avoid harcoding.
---
m4/libdl.m4 | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/m4/libdl.m4 b/m4/libdl.m4
index b24fad832b..98664982ba 100644
--- a/m4/libdl.m4
+++ b/m4/libdl.m4
@@ -1,5 +1,5 @@
# libdl.m4
-# serial 4
+# serial 5
dnl Copyright (C) 2024-2026 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -8,6 +8,18 @@ dnl This file is offered as-is, without any warranty.
dnl From Bruno Haible.
+dnl Set VARIABLE to the shared library name matching REGEXP in the executable
+dnl that AC_LINK_IFELSE has just linked. readelf works when cross-compiling,
+dnl ldd works on more native platforms.
+AC_DEFUN([gl_DLOPEN_SONAME],
+[
+ $1=$(
+ (LC_ALL=C readelf -d conftest$EXEEXT ||
+ LC_ALL=C ldd conftest$EXEEXT) 2>/dev/null |
+ sed -n 's/.*\($2\).*/\1/p'
+ )
+])
+
dnl Set LIBDL to '-ldl' if it is needed to use the functions declared
dnl in <dlfcn.h> (dlopen, dlsym, etc.), or to empty otherwise.
dnl Set HAVE_DLOPEN to 1 if dlopen and dlsym are available, or to 0 otherwise.
@@ -21,7 +33,8 @@ AC_DEFUN([gl_LIBDL],
[gl_cv_lib_dl],
[AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
- [[#include <dlfcn.h>
+ [[#include <stddef.h>
+ #include <dlfcn.h>
]],
[[void *handle = dlopen (NULL, RTLD_LAZY);
return ! (handle && dlsym (handle, "main"));]])],
@@ -32,7 +45,8 @@ AC_DEFUN([gl_LIBDL],
LIBS="$LIBS -ldl"
AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
- [[#include <dlfcn.h>
+ [[#include <stddef.h>
+ #include <dlfcn.h>
]],
[[void *handle = dlopen (NULL, RTLD_LAZY);
return ! (handle && dlsym (handle, "main"));]])],
--
2.47.3
