Segmentation Fault - Port from Windows to Linux

[peter_1998]

Hello

I am trying to solve this problem for two days now and I really dont know what to do anymore.
The application works on windows 7 with this configuration:

Qt 5.10.0 (i386-little_endian-ilp32 shared (dynamic) release build; by MSVC 2015) on "windows"
OS: Windows 7 SP 1 (6.1) [winnt version 6.1.7601]
Architecture: x86_64; features: SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 AVX
Qt Creator 4.6.0-beta1 (4.5.82)

and I want to port it to my raspberry pi with debian stretch:

QT 5.7.1
OS: Raspbian GNU/Linux 9 (stretch)
QT Creator 4.2.0

Compiler on linux is GCC-6 and on windows: MinGW 4.9.2

My problem is:

the app crashes when I call Qapplication with Segmentation Fault .

i tried open a new project on linux and copy the single files to it from the old project but that did not help. I tried to rebuild everything and run qmake but nothing helps.
Help would really be appreciated!!

[mranger90]

I've usually found that this is because of a missing shared library. Run ldd on your application and see if anything is missing.

[peter_1998]

I found the fault , it was one line of code which was completely useless..so annoying!

could somebody explain to me please why this worked in windows but not on linux..very strange: I just deleted the marked line on the first picture below...maybe because the same name ("socket") was used in the header and the source file? I dont know but the windows compiler didnt have any problems with it..