1 files changed, 53 insertions, 0 deletions
diff --git a/lib/free.c b/lib/free.c
new file mode 100644
index 0000000..86ebe6c
--- /dev/null
+++ b/lib/free.c
@@ -0,0 +1,53 @@
+/* Make free() preserve errno.
+
+   Copyright (C) 2003, 2006, 2009-2022 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* written by Paul Eggert */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdlib.h>
+
+/* A function definition is only needed if HAVE_FREE_POSIX is not defined.  */
+#if !HAVE_FREE_POSIX
+
+# include <errno.h>
+
+void
+rpl_free (void *p)
+# undef free
+{
+# if defined __GNUC__ && !defined __clang__
+  /* An invalid GCC optimization
+     <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
+     would optimize away the assignments in the code below, when link-time
+     optimization (LTO) is enabled.  Make the code more complicated, so that
+     GCC does not grok how to optimize it.  */
+  int err[2];
+  err[0] = errno;
+  err[1] = errno;
+  errno = 0;
+  free (p);
+  errno = err[errno == 0];
+# else
+  int err = errno;
+  free (p);
+  errno = err;
+# endif
+}
+
+#endif