1 files changed, 24 insertions, 0 deletions
diff --git a/m4/flock.m4 b/m4/flock.m4
new file mode 100644
index 0000000..655395e
--- /dev/null
+++ b/m4/flock.m4
@@ -0,0 +1,24 @@
+# flock.m4 serial 4
+dnl Copyright (C) 2008-2022 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_FLOCK],
+[
+  AC_REQUIRE([gl_SYS_FILE_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([flock])
+  if test $ac_cv_func_flock = no; then
+    HAVE_FLOCK=0
+  fi
+])
+
+dnl Prerequisites of lib/flock.c.
+AC_DEFUN([gl_PREREQ_FLOCK],
+[
+  AC_CHECK_FUNCS_ONCE([fcntl])
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+
+  dnl Do we have a POSIX fcntl lock implementation?
+  AC_CHECK_MEMBERS([struct flock.l_type],[],[],[[#include <fcntl.h>]])
+])