Add support for declaring 'const fn' in the 'f!' macro

Author: Aaron1011

src/lib.rs

@@ -34,6 +34,7 @@
 #![no_std]
 #![cfg_attr(feature = "rustc-dep-of-std", no_core)]
 #![cfg_attr(target_os = "redox", feature(static_nobundle))]
+#![feature(const_extern_fn)]
 
 #[macro_use]
 mod macros;

src/macros.rs

@@ -123,11 +123,11 @@ macro_rules! s_no_extra_traits {
 
 #[allow(unused_macros)]
 macro_rules! f {
-    ($(pub fn $i:ident($($arg:ident: $argty:ty),*) -> $ret:ty {
+    ($(pub fn $i:ident($($arg:ident: $argty:ty),*) $($constness:ident)* -> $ret:ty  {
         $($body:stmt);*
     })*) => ($(
         #[inline]
-        pub unsafe extern fn $i($($arg: $argty),*) -> $ret {
+        pub $($constness)* unsafe extern fn $i($($arg: $argty),*) -> $ret {
             $($body);*
         }
     )*)

src/unix/linux_like/mod.rs

@@ -1165,7 +1165,7 @@ pub const ARPHRD_IEEE802154: u16 = 804;
 pub const ARPHRD_VOID: u16 = 0xFFFF;
 pub const ARPHRD_NONE: u16 = 0xFFFE;
 
-fn CMSG_ALIGN(len: usize) -> usize {
+const fn CMSG_ALIGN(len: usize) -> usize {
     len + ::mem::size_of::<usize>() - 1 & !(::mem::size_of::<usize>() - 1)
 }
 
@@ -1182,7 +1182,7 @@ f! {
         cmsg.offset(1) as *mut ::c_uchar
     }
 
-    pub fn CMSG_SPACE(length: ::c_uint) -> ::c_uint {
+    pub fn CMSG_SPACE(length: ::c_uint) const -> ::c_uint {
         (CMSG_ALIGN(length as usize) + CMSG_ALIGN(::mem::size_of::<cmsghdr>()))
             as ::c_uint
     }