commit 4e83f4f200f4832280808796694495ebb20070b6
Author: Slávek Banko <slavek.banko@axis.cz>
Date:   Mon Feb 4 17:16:04 2019 +0100

    Make use of TQString::utf8() and TQString::local8Bit() safe for conversion to char*.
    
    Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

diff --git a/src/tools/ntqstring.h b/src/tools/ntqstring.h
index b1ad52b1..4c4c4173 100644
--- a/src/tools/ntqstring.h
+++ b/src/tools/ntqstring.h
@@ -388,6 +388,7 @@ struct Q_EXPORT TQStringData : public TQShared {
     bool security_unpaged : 1;
 
     TQMutex* mutex;
+    TQCString *cString;
 
 private:
 #if defined(TQ_DISABLE_COPY)
diff --git a/src/tools/qstring.cpp b/src/tools/qstring.cpp
index 421ef009..b610a91a 100644
--- a/src/tools/qstring.cpp
+++ b/src/tools/qstring.cpp
@@ -1052,7 +1052,8 @@ TQStringData::TQStringData() : TQShared(),
 	issimpletext(TRUE),
 	maxl(0),
 	islatin1(FALSE),
-	security_unpaged(FALSE) {
+	security_unpaged(FALSE),
+	cString(0) {
 #if defined(TQT_THREAD_SUPPORT) && defined(MAKE_QSTRING_THREAD_SAFE)
 	mutex = new TQMutex(FALSE);
 #endif // TQT_THREAD_SUPPORT && MAKE_QSTRING_THREAD_SAFE
@@ -1066,7 +1067,8 @@ TQStringData::TQStringData(TQChar *u, uint l, uint m) : TQShared(),
 	issimpletext(FALSE),
 	maxl(m),
 	islatin1(FALSE),
-	security_unpaged(FALSE) {
+	security_unpaged(FALSE),
+	cString(0) {
 #if defined(TQT_THREAD_SUPPORT) && defined(MAKE_QSTRING_THREAD_SAFE)
 	mutex = new TQMutex(FALSE);
 #endif // TQT_THREAD_SUPPORT && MAKE_QSTRING_THREAD_SAFE
@@ -1084,6 +1086,9 @@ TQStringData::~TQStringData() {
 	if ( ascii ) {
 		delete[] ascii;
 	}
+	if (cString) {
+		delete cString;
+	}
 #if defined(TQT_THREAD_SUPPORT) && defined(MAKE_QSTRING_THREAD_SAFE)
 	if ( mutex ) {
 		delete mutex;
@@ -1097,6 +1102,10 @@ void TQStringData::setDirty() {
 		delete [] ascii;
 		ascii = 0;
 	}
+	if (cString) {
+		delete cString;
+		cString = 0;
+	}
 	issimpletext = FALSE;
 }
 
@@ -6034,6 +6043,10 @@ TQCString TQString::utf8() const
  	++ch;
     }
     rstr.truncate( cursor - (uchar*)rstr.data() );
+    if (!d->cString) {
+        d->cString = new TQCString;
+    }
+    *d->cString = rstr;
     return rstr;
 }
 
@@ -6235,23 +6248,28 @@ TQString TQString::fromLatin1( const char* chars, int len )
 
 TQCString TQString::local8Bit() const
 {
+    if (!d->cString) {
+        d->cString = new TQCString;
+    }
 #ifdef TQT_NO_TEXTCODEC
-    return latin1();
+    *d->cString = TQCString(latin1());
+    return *d->cString;
 #else
 #ifdef Q_WS_X11
     TQTextCodec* codec = TQTextCodec::codecForLocale();
-    return codec
-	    ? codec->fromUnicode(*this)
-	    : TQCString(latin1());
+    *d->cString = codec ? codec->fromUnicode(*this) : TQCString(latin1());
+    return *d->cString;
 #endif
 #if defined( Q_WS_MACX )
     return utf8();
 #endif
 #if defined( Q_WS_MAC9 )
-    return TQCString(latin1()); //I'm evil..
+    *d->cString = TQCString(latin1()); //I'm evil..
+    return *d->cString;
 #endif
 #ifdef Q_WS_WIN
-    return isNull() ? TQCString("") : qt_winTQString2MB( *this );
+    *d->cString = isNull() ? TQCString("") : qt_winTQString2MB( *this );
+    return *d->cString;
 #endif
 #ifdef Q_WS_QWS
     return utf8(); // ### if there is any 8 bit format supported?