handle zero-size allocations correctly

The `malloc` family of functions may return a null pointer for a
zero-size allocation, which should not be interpreted as an
out-of-memory error.

If the implementation does not return a null pointer, then handling
this will result in memory savings for zero-size types.

This also switches some code to `malloc_raw` in order to maintain a
centralized point for handling out-of-memory in `rt::global_heap`.

Closes #11634

1 files changed, 3 insertions, 5 deletions

diff --git a/src/libextra/c_vec.rs b/src/libextra/c_vec.rs
index 68499cf7032..fc2caa13584 100644
--- a/src/libextra/c_vec.rs
+++ b/src/libextra/c_vec.rs
@@ -160,21 +160,19 @@ impl <T> Container for CVec<T> {
 
 #[cfg(test)]
 mod tests {
-
     use super::*;
 
     use std::libc::*;
     use std::libc;
     use std::ptr;
+    use std::rt::global_heap::malloc_raw;
 
     fn malloc(n: uint) -> CVec<u8> {
         unsafe {
-            let mem = libc::malloc(n as size_t);
-
-            assert!(mem as int != 0);
+            let mem = malloc_raw(n);
 
             CVec::new_with_dtor(mem as *mut u8, n,
-                proc() { libc::free(mem); })
+                proc() { libc::free(mem as *c_void); })
         }
     }