Implement .populate() for map_anon().

Closes #70

src/lib.rs

@@ -482,7 +482,7 @@ impl MmapOptions {
             ));
         }
 
-        MmapInner::map_anon(len, self.stack).map(|inner| MmapMut { inner })
+        MmapInner::map_anon(len, self.stack, self.populate).map(|inner| MmapMut { inner })
     }
 
     /// Creates a raw memory map.

src/stub.rs

@@ -36,7 +36,7 @@ impl MmapInner {
         MmapInner::new()
     }
 
-    pub fn map_anon(_: usize, _: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(_: usize, _: bool, _: bool) -> io::Result<MmapInner> {
         MmapInner::new()
     }
 

src/unix.rs

@@ -162,12 +162,13 @@ impl MmapInner {
     }
 
     /// Open an anonymous memory map.
-    pub fn map_anon(len: usize, stack: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(len: usize, stack: bool, populate: bool) -> io::Result<MmapInner> {
         let stack = if stack { MAP_STACK } else { 0 };
+        let populate = if populate { MAP_POPULATE } else { 0 };
         MmapInner::new(
             len,
             libc::PROT_READ | libc::PROT_WRITE,
-            libc::MAP_PRIVATE | libc::MAP_ANON | stack,
+            libc::MAP_PRIVATE | libc::MAP_ANON | stack | populate,
             -1,
             0,
         )

src/windows.rs

@@ -340,7 +340,7 @@ impl MmapInner {
         Ok(inner)
     }
 
-    pub fn map_anon(len: usize, _stack: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(len: usize, _stack: bool, _populate: bool) -> io::Result<MmapInner> {
         // Ensure a non-zero length for the underlying mapping
         let mapped_len = len.max(1);
         unsafe {