Linux application crashes.
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@JonB said in Linux application crashes.:
@jenya7
When it stops find the stack trace (not disassembly) pane of the debugger. That may contain a clue as to where it is coming from.Just one thought: you have a
static QString, created before theQCoreApplication. Although this should be OK for aQString, if you have some otherstaticQt objects elsewhere they might cause a problem. Do you?Can not find the stack trace window.
Of course I have static objects, plenty in every file. If I don't declare it as static - I get -
warning: no previous extern declaration for non-static variable
And it's perfectly right - it's data encapsulation.I see a Stack window but it's empty.
@jenya7 said in Linux application crashes.:
And it's perfectly right - it's data encapsulation
No, having global/static objects is not a great idea. In any case, as I said a large number of Qt objects cannot/must not be defined as static/global, because they cannot be instantiated before
QCoreApplicationhas been created, whether you think that is a good idea or not.Try this now for your test program:
#include <stdio.h> int main(int argc, char *argv[]) { printf ("Hello World\n"); return 0; }If that gives the same behaviour --- as I am hoping it will, then you know you do not have a Qt issue.
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@jsulm said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
Of course I have static objects, plenty in every file
Why? You should avoid static variables as much as possible.
"warning: no previous extern declaration for non-static variable" - C++ is an object oriented language, you should not need too many stand alone variables, use class members instead. Please show one example where you get this eeror, so we can suggest a solution.
"Can not find the stack trace window" - it's right there in debug view.
I see. Indeed the variables are not members of a class. I have some files without classes. Could be the issue?
I removed all static objects. For now it looks like this
#include <QCoreApplication> //#include "udp.h" //#include "sys.h" //static QString sys_params_file; int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); printf ("Hello\n"); return a.exec(); }Still the same problem. The exception arises at _start function, it's before my app comes in play as I understand.
@jenya7 said in Linux application crashes.:
The exception arises at _start function, it's before my app comes in play as I understand.
Could indicate that some libs or Qt plug-ins are not found/loaded.
Set QT_DEBUG_PLUGINS in Run settings of your app and see what output you get (you can also post it here).
How did you install Qt? -
@jenya7 said in Linux application crashes.:
The exception arises at _start function, it's before my app comes in play as I understand.
Could indicate that some libs or Qt plug-ins are not found/loaded.
Set QT_DEBUG_PLUGINS in Run settings of your app and see what output you get (you can also post it here).
How did you install Qt?@jsulm said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
The exception arises at _start function, it's before my app comes in play as I understand.
Could indicate that some libs or Qt plug-ins are not found/loaded.
Set QT_DEBUG_PLUGINS in Run settings of your app and see what output you get (you can also post it here).
How did you install Qt?I installed it like this
sudo apt-get update sudo apt-get upgrade sudo apt-get install qt5-default sudo apt-get install qtcreator sudo apt-get install qtdeclarative5-dev sudo apt-get install qtbase5-examples sudo apt-get install qtbase5-doc-htmlI found a widget app, I created several months ago - it runs, no problem. It also has in a *.pro file
QT += core
QT += network
QT += xml
I thought one of these causes the problem.
How do I set QT_DEBUG_PLUGINS? -
@jenya7 said in Linux application crashes.:
And it's perfectly right - it's data encapsulation
No, having global/static objects is not a great idea. In any case, as I said a large number of Qt objects cannot/must not be defined as static/global, because they cannot be instantiated before
QCoreApplicationhas been created, whether you think that is a good idea or not.Try this now for your test program:
#include <stdio.h> int main(int argc, char *argv[]) { printf ("Hello World\n"); return 0; }If that gives the same behaviour --- as I am hoping it will, then you know you do not have a Qt issue.
@JonB said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
And it's perfectly right - it's data encapsulation
No, having global/static objects is not a great idea. In any case, as I said a large number of Qt objects cannot/must not be defined as static/global, because they cannot be instantiated before
QCoreApplicationhas been created, whether you think that is a good idea or not.Try this now for your test program:
#include <stdio.h> int main(int argc, char *argv[]) { printf ("Hello World\n"); return 0; }If that gives the same behaviour --- as I am hoping it will, then you know you do not have a Qt issue.
The same problem.
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@jsulm said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
The exception arises at _start function, it's before my app comes in play as I understand.
Could indicate that some libs or Qt plug-ins are not found/loaded.
Set QT_DEBUG_PLUGINS in Run settings of your app and see what output you get (you can also post it here).
How did you install Qt?I installed it like this
sudo apt-get update sudo apt-get upgrade sudo apt-get install qt5-default sudo apt-get install qtcreator sudo apt-get install qtdeclarative5-dev sudo apt-get install qtbase5-examples sudo apt-get install qtbase5-doc-htmlI found a widget app, I created several months ago - it runs, no problem. It also has in a *.pro file
QT += core
QT += network
QT += xml
I thought one of these causes the problem.
How do I set QT_DEBUG_PLUGINS?@jenya7 said in Linux application crashes.:
How do I set QT_DEBUG_PLUGINS?
Right side in QtCreator->Projects->Run->Run Environment, then add there QT_DEBUG_PLUGINS with value 1.
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@JonB said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
And it's perfectly right - it's data encapsulation
No, having global/static objects is not a great idea. In any case, as I said a large number of Qt objects cannot/must not be defined as static/global, because they cannot be instantiated before
QCoreApplicationhas been created, whether you think that is a good idea or not.Try this now for your test program:
#include <stdio.h> int main(int argc, char *argv[]) { printf ("Hello World\n"); return 0; }If that gives the same behaviour --- as I am hoping it will, then you know you do not have a Qt issue.
The same problem.
@jenya7
As I suspected :( You could now also remove the#include <stdio.h>and theprintf()just to rule out any possible I/O issue.Assuming that too fails, you have a problem!
What Linux are you on, are you fully patched, I assume your
gcccame with the OS, does that need updating?Since this means you cannot run any C/C++ program, how long has this been happening to you? Is this the first time you have ever tried, or did it use to work but not now?
Experiments with Qt and
QT_DEBUG_PLUGINSare now pointless, since your fault occurs with nothing Qt in your program. You should even be able to compile the minimal program with justgcc file.cand then run the executable (a.out), so not even using anything Qt to build.Try compiling for Release versus Debug, does that make any difference? Try running your executable from the command-line, not from Qt Creator, does that make any difference?
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@jenya7
As I suspected :( You could now also remove the#include <stdio.h>and theprintf()just to rule out any possible I/O issue.Assuming that too fails, you have a problem!
What Linux are you on, are you fully patched, I assume your
gcccame with the OS, does that need updating?Since this means you cannot run any C/C++ program, how long has this been happening to you? Is this the first time you have ever tried, or did it use to work but not now?
Experiments with Qt and
QT_DEBUG_PLUGINSare now pointless, since your fault occurs with nothing Qt in your program. You should even be able to compile the minimal program with justgcc file.cand then run the executable (a.out), so not even using anything Qt to build.Try compiling for Release versus Debug, does that make any difference? Try running your executable from the command-line, not from Qt Creator, does that make any difference?
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@JonB
From a build folder it runs good.
Non-debug run - also good.
It happens only in Debug run.@jenya7
For your test program you don't need anything Qt. Remove all thoseQT += core-type lines from.profile. Runs OK from command-line, outside Creator? Errors only when run inside Creator? From Creator, when you run it have you tried both "Run without debugging" and "Run with debugger"? -
@JonB
From a build folder it runs good.
Non-debug run - also good.
It happens only in Debug run. -
@jenya7 said in Linux application crashes.:
It happens only in Debug run.
Try running it under gdb from outside Qt Creator. From a command-line you can just go:
gdb /full/path/to/executableand then IIRC type
run<RETURN>inside gdb prompt.@JonB said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
It happens only in Debug run.
Try running it under gdb from outside Qt Creator. From a command-line you can just go:
gdb /full/path/to/executableand then IIRC type
run<RETURN>inside gdb prompt.This way it runs good.
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@JonB said in Linux application crashes.:
@jenya7 said in Linux application crashes.:
It happens only in Debug run.
Try running it under gdb from outside Qt Creator. From a command-line you can just go:
gdb /full/path/to/executableand then IIRC type
run<RETURN>inside gdb prompt.This way it runs good.
@jenya7
So if this is all true, and you have tried the various suggestions for within Creator, it looks like there is some problem when Creator invoked gdb, doesn't it?I don't know what is wrong. You could check your version of Creator is up-to-date. And that the kit is running the desired gdb executable. I suppose you might try uninstalling and reinstalling Creator, just in case. Until someone else posts a better solutuon.
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@jenya7
So if this is all true, and you have tried the various suggestions for within Creator, it looks like there is some problem when Creator invoked gdb, doesn't it?I don't know what is wrong. You could check your version of Creator is up-to-date. And that the kit is running the desired gdb executable. I suppose you might try uninstalling and reinstalling Creator, just in case. Until someone else posts a better solutuon.
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@jenya7
Then create a brand new tiny test project from scratch and try that. If that works, go back to existing project and delete everything from the build output directory, runqmakeand re-build, maybe that will clear it up?
