Problem setting up Curl

GeertDaelemans

I am trying to revive a project witten in an older version of Qt. It contains implementations based upon cUrl.
But I don't seem to get the cUrl stuff to work. It builds seemingly ok, but then keeps crashing (The program has unexpectedly finished.)

Btw I am a newbie at this...

For demonstration purposes I have reduced my code to the absolute minimum.

Error message:

11:54:25: Starting D:\Workspaces\build-Curl-Desktop_Qt_5_12_11_MinGW_32_bit-Debug\debug\Curl.exe ...
11:54:25: The program has unexpectedly finished.
11:54:25: The process was ended forcefully.
11:54:25: D:\Workspaces\build-Curl-Desktop_Qt_5_12_11_MinGW_32_bit-Debug\debug\Curl.exe crashed.

My .pro file:

QT -= gui

CONFIG += c++11 console
CONFIG -= app_bundle

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
        main.cpp

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

win32: LIBS += -L$$PWD/../libs/curl-7.64.0-win32-mingw/lib/ -lcurl

INCLUDEPATH += $$PWD/../libs/curl-7.64.0-win32-mingw/include
DEPENDPATH += $$PWD/../libs/curl-7.64.0-win32-mingw/include

The main.cpp

#include <QCoreApplication>
#include <curl/curl.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    CURL *curl = curl_easy_init();
    curl_easy_cleanup(curl);

    return a.exec();
}

SGaist

Hi,

Did you check that the curl dll can be loaded at run time by your application ?

If not, either copy the dll in the build folder or add the path to the curl dll to the PATH environment variable in the Run part of the Project panel.

GeertDaelemans

Everyday I get smarter and smarter... thanks, that did the trick! ;-)

Btw do you know of any good resources that would help a newbie like me to get these external libraries explained? And how to package them correctly?

Thank you very much,

Geert

SGaist

The rules on Windows to avoid DLL hell are pretty simple:

Deploy the dlls your application requires in the same folder as your executable (plugins like Qt's own can live in different folders though).
Do NOT install any dll in system folders. This can have unexpected side effects and wreak havoc.
Unless really required (most of the time it's not), do not modify the PATH environment variable.