net/http: document ResponseWriter.WriteHeader more

Change-Id: I65209b90ed7c56d4c751b3e4b3ce1de52dae368c
Reviewed-on: https://go-review.googlesource.com/82635
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/net/http/server.go b/src/net/http/server.go
index 3fa666016490519d6c84f502a793c824deaf911c..e1698ccfa323128eca408fb9f1c76f913757b986 100644 (file)
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -132,12 +132,20 @@ type ResponseWriter interface {
        // possible to maximize compatibility.
        Write([]byte) (int, error)
 
-       // WriteHeader sends an HTTP response header with status code.
+       // WriteHeader sends an HTTP response header with the provided
+       // status code.
+       //
        // If WriteHeader is not called explicitly, the first call to Write
        // will trigger an implicit WriteHeader(http.StatusOK).
        // Thus explicit calls to WriteHeader are mainly used to
        // send error codes.
-       WriteHeader(int)
+       //
+       // The provided code must be a valid HTTP 1xx-5xx status code.
+       // Only one header may be written. Go does not currently
+       // support sending user-defined 1xx informational headers,
+       // with the exception of 100-continue response header that the
+       // Server sends automatically when the Request.Body is read.
+       WriteHeader(statusCode int)
 }
 
 // The Flusher interface is implemented by ResponseWriters that allow