Redirect stderr to log window

Author: bbogush

qt/logger.cpp

@@ -60,10 +60,13 @@ void Logger::logHandler(QtMsgType type, const QMessageLogContext &context ,
 Logger::Logger()
 {
     qInstallMessageHandler(logHandler);
+    oldBuf = std::cerr.rdbuf();
+    std::cerr.rdbuf(this);
 }
 
 Logger::~Logger()
 {
+    std::cerr.rdbuf(oldBuf);
     qInstallMessageHandler(nullptr);
 }
 
@@ -97,3 +100,15 @@ void Logger::setTextEdit(QTextEdit *textEdit)
     logTextEdit = textEdit;
 }
 
+std::basic_streambuf<char>::int_type Logger::overflow(int_type v)
+{
+    return v;
+}
+
+std::streamsize Logger::xsputn(const char *p, std::streamsize n)
+{
+    qCritical() << p;
+
+    return n;
+}
+

qt/logger.h

@@ -7,18 +7,26 @@
 #define LOGGER_H
 
 #include <QTextEdit>
+#include <iostream>
+#include <streambuf>
 
-class Logger
+class Logger: public std::basic_streambuf<char>
 {
     static QTextEdit *logTextEdit;
     static Logger *logger;
     static int refCount;
+    std::streambuf *oldBuf;
 
     explicit Logger();
     ~Logger();
 
     static void logHandler(QtMsgType type, const QMessageLogContext &context,
         const QString &msg);
+
+protected:
+    virtual std::basic_streambuf<char>::int_type overflow(int_type v) override;
+    virtual std::streamsize xsputn(const char *p, std::streamsize n) override;
+
 public:
     static Logger *getInstance();
     static void putInstance();