add QProcess::Forwarded{Output,Error}Channel

Change-Id: Ifc5ed20c38f3228ef25c28681f296d0456b61abe
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/src/corelib/io/qprocess.cpp b/src/corelib/io/qprocess.cpp
index d473281acc..27a8bce3fe 100644
--- a/src/corelib/io/qprocess.cpp
+++ b/src/corelib/io/qprocess.cpp
@@ -533,7 +533,11 @@ void QProcessPrivate::Channel::clear()
     MergedChannels before starting the process to activative
     this feature. You also have the option of forwarding the output of
     the running process to the calling, main process, by passing
-    ForwardedChannels as the argument.
+    ForwardedChannels as the argument. It is also possible to forward
+    only one of the output channels - typically one would use
+    ForwardedErrorChannel, but ForwardedOutputChannel also exists.
+    Note that using channel forwarding is typically a bad idea in GUI
+    applications - you should present errors graphically instead.
 
     Certain processes need special environment settings in order to
     operate. You can set environment variables for your process by
@@ -625,6 +629,17 @@ void QProcessPrivate::Channel::clear()
     writes to its standard output and standard error will be written
     to the standard output and standard error of the main process.
 
+    \value ForwardedErrorChannel QProcess manages the standard output
+    of the running process, but forwards its standard error onto the
+    main process. This reflects the typical use of command line tools
+    as filters, where the standard output is redirected to another
+    process or a file, while standard error is printed to the console
+    for diagnostic purposes.
+    (This value was introduced in Qt 5.2.)
+
+    \value ForwardedOutputChannel Complementary to ForwardedErrorChannel.
+    (This value was introduced in Qt 5.2.)
+
     \note Windows intentionally suppresses output from GUI-only
     applications to inherited consoles.
     This does \e not apply to output redirected to files or pipes.