1 files changed, 44 insertions, 0 deletions
diff --git a/m4/ioctl.m4 b/m4/ioctl.m4
new file mode 100644
index 0000000..835338a
--- /dev/null
+++ b/m4/ioctl.m4
@@ -0,0 +1,44 @@
+# ioctl.m4 serial 5
+dnl Copyright (C) 2008-2018 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_IOCTL],
+[
+  AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
+  HAVE_IOCTL=1
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    dnl Even if the 'socket' module is not used here, another part of the
+    dnl application may use it and pass file descriptors that refer to
+    dnl sockets to the ioctl() function. So enable the support for sockets.
+    HAVE_IOCTL=0
+  else
+    AC_CHECK_FUNCS([ioctl])
+    dnl On glibc systems, the second parameter is 'unsigned long int request',
+    dnl not 'int request'. We cannot simply cast the function pointer, but
+    dnl instead need a wrapper.
+    AC_CACHE_CHECK([for ioctl with POSIX signature],
+      [gl_cv_func_ioctl_posix_signature],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/ioctl.h>
+              /* On some platforms, ioctl() is declared in <unistd.h>.  */
+              #include <unistd.h>
+            ]],
+            [[extern
+              #ifdef __cplusplus
+              "C"
+              #endif
+              int ioctl (int, int, ...);
+            ]])
+         ],
+         [gl_cv_func_ioctl_posix_signature=yes],
+         [gl_cv_func_ioctl_posix_signature=no])
+      ])
+    if test $gl_cv_func_ioctl_posix_signature != yes; then
+      REPLACE_IOCTL=1
+    fi
+  fi
+])