diff --git a/base/io.jl b/base/io.jl
index e162996d58fe5..ad81a4075998d 100644
--- a/base/io.jl
+++ b/base/io.jl
@@ -295,7 +295,9 @@ julia> rm("myfile.txt")
 function open(f::Function, args...; kwargs...)
     io = open(args...; kwargs...)
     try
-        f(io)
+        v = f(io)
+        flush(io)
+        return v
     finally
         close(io)
     end