Write directly to stdout/err

Cargo.toml

@@ -25,8 +25,9 @@ log-panic = ["log-panics"]
 timestamp = ["chrono"]
 
 [dependencies]
-log        = { version = "0.4", features = ["std"] }
 chrono     = { version = "0.4", optional = true }
+libc       = { version = "0.2.58" }
+log        = { version = "0.4", features = ["std"] }
 log-panics = { version = "2", optional = true, features = ["with-backtrace"] }
 
 [dev-dependencies]

src/lib.rs

@@ -423,16 +423,52 @@ fn log_failure(err: io::Error) {
 // though the return type of the functions are different we only need them both
 // to implement `io::Write`.
 
+#[cfg(not(test))]
+struct Stdout;
+
+#[cfg(not(test))]
+impl Write for Stdout {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match unsafe { libc::write(libc::STDOUT_FILENO, buf.as_ptr() as *const libc::c_void, buf.len()) } {
+            n if n < 0 => Err(io::Error::last_os_error()),
+            n => Ok(n as usize),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        // Don't have to flush standard out.
+        Ok(())
+    }
+}
+
 #[cfg(not(test))]
 #[inline(always)]
-fn stdout() -> io::Stdout {
-    io::stdout()
+fn stdout() -> Stdout {
+    Stdout
+}
+
+#[cfg(not(test))]
+struct Stderr;
+
+#[cfg(not(test))]
+impl Write for Stderr {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match unsafe { libc::write(libc::STDERR_FILENO, buf.as_ptr() as *const libc::c_void, buf.len()) } {
+            n if n < 0 => Err(io::Error::last_os_error()),
+            n => Ok(n as usize),
+        }
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        // Don't have to flush standard error.
+        Ok(())
+    }
 }
 
 #[cfg(not(test))]
 #[inline(always)]
-fn stderr() -> io::Stderr {
-    io::stderr()
+fn stderr() -> Stderr {
+    Stderr
 }
 
 // The testing variant of the functions.