How to use precompiled headers (pch) for C++ with Qt

[JacobNovitsky]

Tried to google a little, but information is not much consistent...
Need to build faster my custom headers and Qt core/gui/widgets headers too

[ChrisW67]

qmake: Using Precompiled Headers
cmake: target_precompile_headers

[JacobNovitsky]

@ChrisW67 thanks :)
do you have real code sample I could refer to?

as I can see the process, I need to insert

/* Add C includes here */

#if defined __cplusplus
/* Add C++ includes here */

# include <iostream>
# include <QApplication>
# include <QPushButton>
# include <QLabel>
#endif

before every qt header and add smth to qt pro file?

[mpergand]

@JacobNovitsky
Here my own example:

.pro file

CONFIG +=   precompile_header
PRECOMPILED_HEADER = $$PWD/Application/Headers.pch

Headers.pch

// Prefix header 

#ifdef __cplusplus
										
#include "QtMacros.h"
#include "QtAppDefs.h"

#endif

And you don't need to insert anything in your .h .cpp files.

[JacobNovitsky]

@mpergand is it nessesary to change .h to .pch or I can use .h file too?

[ChrisW67]

@JacobNovitsky Call the file whatever you like.

[JacobNovitsky]

@ChrisW67 how to test if its already pre-compiled, my complier does not compile this particular header?
https://forum.qt.io/topic/151001/additional-info-upon-compiling-with-qt-creator

[ChrisW67]

@JacobNovitsky Please stop creating new threads for the same conversation.

[Christian Ehrlicher]

Dupe of https://forum.qt.io/topic/150964/how-to-set-needed-permission-so-i-can-edit-qt-headers-from-qt-creator/6