Allow qDebug output to be configured by qSetMessagePattern()

Add qSetMessagePattern() to configure the default
message pattern. This one can still be overwritten by setting the
QT_MESSAGE_PATTERN environment variable.

Without this method, there's actually no way to change the
default output programatically. Since QT_MESSAGE_PATTERN is
evaluated when the first message arrives, setting it via e.g. qputenv
might have no effect/be too late.

Change-Id: I115e0c30606f128fdbf5c169a951ffa2a6a48517
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/auto/corelib/global/qlogging/app/main.cpp b/tests/auto/corelib/global/qlogging/app/main.cpp
index dfa52315c7..2f5a975e43 100644
--- a/tests/auto/corelib/global/qlogging/app/main.cpp
+++ b/tests/auto/corelib/global/qlogging/app/main.cpp
@@ -51,8 +51,15 @@ int main(int argc, char **argv)
     QCoreApplication app(argc, argv);
     app.setApplicationName("tst_qlogging");
 
+    qSetMessagePattern("[%{type}] %{message}");
+
     qDebug("qDebug");
     qWarning("qWarning");
     qCritical("qCritical");
+
+    qSetMessagePattern(QString());
+
+    qDebug("qDebug2");
+
     return 0;
 }