QT tutorial

Ephracis · 11-11-2004, 04:11 AM

I am trying to learn qt. But now when coming to compiling several files it seems to be something wrong.

I have three files in a directory called t7.
To make sure I haven't typed anything wrong I have copied and paste the text from the three files in the tutorial. The files are:
lcdrange.h
lcdrange.cpp
main.cpp

Now here is the error:

Code:

mezzymeat@garanka:/User/programming/qt/t7$ g++ -I/usr/local/qt/include/ -L/usr/local/qt/lib/ -lqt lcdrange.cpp main.cpp
/tmp/ccm135p8.o(.text+0x1f): In function `LCDRange::LCDRange[not-in-charge](QWidget*, char const*)':
: undefined reference to `vtable for LCDRange'
/tmp/ccm135p8.o(.text+0x2b): In function `LCDRange::LCDRange[not-in-charge](QWidget*, char const*)':
: undefined reference to `vtable for LCDRange'
/tmp/ccm135p8.o(.text+0x1b9): In function `LCDRange::LCDRange[in-charge](QWidget*, char const*)':
: undefined reference to `vtable for LCDRange'
/tmp/ccm135p8.o(.text+0x1c5): In function `LCDRange::LCDRange[in-charge](QWidget*, char const*)':
: undefined reference to `vtable for LCDRange'
collect2: ld returned 1 exit status

rjlee · 11-11-2004, 05:05 AM

This code uses signals and slots, which Qt implements swith the MetaObject Compiler (moc).

You need to run this source code through moc, to generate the metaobject files *_moc.cpp, and compile these files as well.

Ephracis · 11-11-2004, 05:57 AM

Quote:

Originally posted by rjlee
This code uses signals and slots, which Qt implements swith the MetaObject Compiler (moc).

You need to run this source code through moc, to generate the metaobject files *_moc.cpp, and compile these files as well.

How do I run source through moc to create these files?

EDIT:

I checked out man moc and it was right. :P
But I could not generate moc-files correctly, they become empty.

Code:

mezzymeat@garanka:/User/programming/qt/t7$ moc -o lcdrange.moc lcdrange.cpp 
lcdrange.cpp:0: Warning: No relevant classes found. No output generated.
mezzymeat@garanka:/User/programming/qt/t7$ moc -o main.moc main.cpp         
main.cpp:0: Warning: No relevant classes found. No output generated.

Also even tried to do the same with the headerfile but same result there. The files are still exactly the same as the examples.

phoenix7 · 11-11-2004, 12:21 PM

I think your problem is about making (linking).
you shouldn't need to change your code.

phoenix7 · 11-11-2004, 12:22 PM

do you know qmake?

you can try these :

Code:

qmake -project

Code:

qmake

Code:

make

I wish this solve your problem?

Ephracis · 11-11-2004, 12:44 PM

Yeah I know about qmake but I like to compile by myself, I feel that I learn more then. But I did qmake and saw which commands that were used.

If anyone else would have this problem here is how to compile it:

First create object-files of all the source-files (not the headers).
Then run moc on the headerfile.
After that do the same with the new moc-file (create an object-file).
At last link the object-files together and create the binary.

I rather understand this then just knowing how to spell to "qmake -project". :P