flush STDOUT before sleep

Author: fglock

src/main/java/org/perlonjava/runtime/RuntimeIO.java

@@ -64,7 +64,7 @@ public class RuntimeIO implements RuntimeScalarReference {
 
     // State flags
     private boolean isEOF;
-    private boolean needFlush;
+    boolean needFlush;
 
     // Constructor to initialize buffers
     public RuntimeIO() {

src/main/java/org/perlonjava/runtime/RuntimeScalar.java

@@ -25,6 +25,8 @@
 import java.util.concurrent.TimeUnit;
 
 import static org.perlonjava.runtime.GlobalContext.getGlobalVariable;
+import static org.perlonjava.runtime.RuntimeIO.stderr;
+import static org.perlonjava.runtime.RuntimeIO.stdout;
 import static org.perlonjava.runtime.RuntimeScalarCache.*;
 
 /**
@@ -1560,6 +1562,15 @@ public RuntimeScalar hex() {
     }
 
     public RuntimeScalar sleep() {
+
+        // Flush stdout and stderr before reading, in case we are displaying a prompt
+        if (stdout.needFlush) {
+            stdout.flush();
+        }
+        if (stderr.needFlush) {
+            stderr.flush();
+        }
+
         long s = (long) this.getDouble() * 1000;
         try {
             TimeUnit.MILLISECONDS.sleep(s);