Room for nwp and Sun Maung Oo

Sun Maung Oo

5:55 PM

Does any one have experience with QT? I am having a problem on it

@Borgleader , I think it's a well asked question but I don't understand part of it. I guess chat room is the best way to go so here I am (am I wrong?)

Here it's goes. I get the "warning: Exception at 0x7ffcce80c0b4, code: 0xc0000135: DLL not found, flags=0x1 (execution cannot be continued) (first chance)" error message on qt. Is there any way to figure out which DLL (I mean dll name) was not found

Its also show some asm code in the windows

Sun Maung Oo

6:23 PM

@nwp, I try dependency walker on the ".a" file but it doesn't show anything. I am getting the lib from "https://mpv.srsfckn.biz/"

@nwp, There is no ".exe" yet since I cannot build the source code. The lib file provided in the zip does not have a ".exe"

@nwp, Doesn't process monitor require ".exe" to be run

?

@nwp, Sorry, I didn't make myself clear. I want to use the lib provided by https://mpv.srsfckn.biz/ to write a program. I have added
"
LIBS += -L$$PWD/mpv-dev/lib/mpv-1.dll
LIBS += $$PWD/mpv-dev/lib/libmpv.dll.a
"

and it show me https://postimg.org/image/gesi42r9d/

@nwp, When I remove the "-L" argument, it show "error: LNK1107: invalid or corrupt file: cannot read at 0x3E0"

Sun Maung Oo

6:55 PM

@nwp, My end result : wanted to use the lib in (http://mpv.srsfckn.biz) in QT (Windows).

Method tested : try with various "LIBS" argument and various argument in ".pro" file

Current situation : Don't know head or tail of what I should try next. In need of serious help. Have been trying for more than 1 day.

hello

nwp

there are a couple of things wrong there

Sun Maung Oo

ok

nwp

first: are you using gcc or VS?

Sun Maung Oo

VS

nwp

ok

so "LIBS += " adds libraries

dll's are not libraries in that sense

so LIBS += some.dll doesn't work

Sun Maung Oo

6:59 PM

I see

nwp

you probably need to keep the LIBS += something.a

Sun Maung Oo

LIBS += $$PWD/mpv-dev/lib/libmpv.dll.a

nwp

the .dll needs to go in the executable directory

since your are using Qt Creator you should be able to press CTRL+B to build your stuff

does it print an error after building?

Sun Maung Oo

:-1: error: Exception at 0x7ffc91ebc6e8, code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance)

nwp

that is weird... this looks like an exception that happens when a program is run, not when you build a program

there should be a "compile output" window somewhere, what does it say?

Sun Maung Oo

7:03 PM

01:33:18: Running steps for project MPCPort...
01:33:18: Configuration unchanged, skipping qmake step.
01:33:18: Starting: "C:\Qt\Qt5.5.0\Tools\QtCreator\bin\jom.exe"
C:\Qt\Qt5.5.0\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
C:\Qt\Qt5.5.0\5.5\msvc2013_64\bin\uic.exe ..\MPCPort\mainwindow.ui -o ui_mainwindow.h
cl -c -nologo -Zc:wchar_t -FS -Zi -MDd -GR -W3 -w34100 -w34189 -w44996 -EHsc /Fddebug\MPCPort.pdb -DUNICODE -DWIN32 -DWIN64 -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I..\MPCPort -I. -I..\MPCPort\mpv-dev\include -I..\..\Qt\Qt5.5.0\5.5\msvc2013_64\include -I..\..\Qt\Qt5.5.0\5.5\msvc…

nwp

so it correctly built an executable

Sun Maung Oo

yes

nwp

did you find the folder where it put the MPCPort.exe into?

Sun Maung Oo

I do

nwp

did you copy the .dll into there?

Sun Maung Oo

7:06 PM

I copy all the QT dll + mpv-1.dll and libmpv.dll.a

nwp

the .a doesn't help, libmpv.dll should do it

after you copy the dll in there and it still doesn't work you can open the MPCPort.exe with dependency walker and it should tell you what you are missing

Sun Maung Oo

This is the dll I am provided

postimg.org/image/aplv6p6qv

nwp

ok, when you just try to start the MPCPort.exe, what does it say?

Sun Maung Oo

It crash

The dependency walker show error

postimg.org/image/4uh8sezjl

nwp

@SunMaungOo got to scroll around to find which dll is missing

Sun Maung Oo

7:13 PM

API-MS-WIN-CORE-KERNEL32-PRIVATE-L1-1-1.DLL
API-MS-WIN-CORE-PRIVATEPROFILE-L1-1-1.DLL
API-MS-WIN-SERVICE-PRIVATE-L1-1-1.DLL
API-MS-WIN-CORE-SHUTDOWN-L1-1-1.DLL
EXT-MS-WIN-NTUSER-UICONTEXT-EXT-L1-1-0.DLL
IESHIMS.DLL

nwp

none of these look relevant

unfortunately dependency walker shows some false positives

Sun Maung Oo

I also thought it is not relevant

are you on Windows system?

nwp

no, but you can run dependency walker on some random other executable, like dependency walker itself and it will show these same dlls missing

they are not really missing, dependency walker is just bad

Sun Maung Oo

Could you help me compile? I can give you the lib file

nwp

anyways, you can try going with the process monitor route to find out which dll your exe wants

the lib file is VS only, VS doesn't work under linux

Sun Maung Oo

7:17 PM

Oh, you are on linux

nwp

I've had similar issues at work with VS

another thing that could be the issue is that the library was made with another version of VS than what you are using

Sun Maung Oo

what am I looking at Process Monitor?

nwp

there should be a files tab that shows which files are accessed and the success status

Sun Maung Oo

I don't know which tab do you mean?

postimg.org/image/7fgc971l3

nwp

the selected symbols are like registry, files, network, something

we are only interested in files

then you click some other icon to start monitoring and it should spam a lot of activities

then you need to filter it down a bit, for example only display file open that failed

then you clean all events, run the exe, stop monitoring and filter by program name probably

then you should find which dll it tried and failed to open

Sun Maung Oo

7:27 PM

Ok, I have filter down to the process

I filter it down

postimg.org/image/au0eioi6v

nwp

well, it should be the last one, but it doesn't seem to be related to mpv

are you doing something bcrypt-related?

Sun Maung Oo

No

#-------------------------------------------------
#
# Project created by QtCreator 2016-07-08T23:06:23
#
#-------------------------------------------------

QT += core gui

INCLUDEPATH += $$PWD/mpv-dev/include
CONFIG += c++11
CONFIG += debug

LIBS += $$PWD/mpv-dev/lib/libmpv.dll.a

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = MPCPort
TEMPLATE = app

SOURCES += main.cpp\
mainwindow.cpp \
mpvwidget.cpp

HEADERS += mainwindow.h \
mpvwidget.h

FORMS += mainwindow.ui

mpvwidget.h

#ifndef MPVWIDGET_H
#define MPVWIDGET_H

#include <mpv/client.h>
#include <mpv/opengl_cb.h>
#include <mpv/qthelper.hpp>

class MpvWidget
{
public:
MpvWidget();

~MpvWidget();

private:
\
void init();

mpv_opengl_cb_context* context;
};

#endif // MPVWIDGET_H

mpvwidget.cpp

#include "mpvwidget.h"

MpvWidget::MpvWidget()
{
init();
}

MpvWidget::~MpvWidget()
{

mpv_opengl_cb_uninit_gl(context);

}

static void* on_frame_ready(void *ctx, const char *name)
{
void *res;

return res;
}

void MpvWidget::init()
{

if(mpv_opengl_cb_init_gl(context,NULL,on_frame_ready,NULL)<0)
{
throw std::runtime_error("[MpvWidget] cb init gl failed.");
}

}

That is my whole source code since I am trying to compile it first

nwp

well it compiled already

void *res;
return res;

this would probably crash

maybe it is not actually a dll issue

Sun Maung Oo

technically, it compile but the error show up

postimg.org/image/fzal5oy4x

when running it

nwp

ok this is starting to make sense

the error message says the program tried to read address 0, which it cannot

Sun Maung Oo

7:42 PM

I am new to C++ so I have no experience solving pointer and memory access error

I used to program C#

nwp

in the line where it crashed you are passing NULL twice, plus I think you never instantiated context

do you have documentation for the mpv_*-functions?

Sun Maung Oo

I do

nwp

it should say what you can and cannot pass to mpv_opengl_init, you probably passed NULL or context to something that you were not supposed to

Sun Maung Oo

I will paste the doc please wait

client.h

pastebin.com/NgjYLcRZ

nwp

@SunMaungOo that file doesn't seem to contain the function mpv_opengl_cb_init_gl

Sun Maung Oo

7:49 PM

Sorry, I upload a wrong file

this is the correct file

opengl_cb.h

pastebin.com/tB1jVgsZ

nwp

I have a hunch: change mpv_opengl_cb_context* context; to mpv_opengl_cb_context context; and mpv_opengl_cb_init_gl(context, ... to mpv_opengl_cb_init_gl(&context, ...

Sun Maung Oo

C:\QT Test\MPCPort\mpvwidget.h:19: error: C2079: 'MpvWidget::context' uses undefined struct 'mpv_opengl_cb_context'

C:\QT Test\MPCPort\mpvwidget.cpp:66: error: C2664: 'int mpv_opengl_cb_init_gl(mpv_opengl_cb_context *,const char *,mpv_opengl_cb_get_proc_address_fn,void *)' : cannot convert argument 1 from 'int *' to 'mpv_opengl_cb_context *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

C:\QT Test\MPCPort\mpvwidget.h:19: error: C2079: 'MpvWidget::context' uses undefined struct 'mpv_opengl_cb_context'

nwp

also be careful with returning pointers to local variables: in on_frame_ready char c; is created, then you return a pointer to c, then c disappears. If someone uses that pointer the program crashes or behaves weird.

@SunMaungOo ok, seems like my hunch was wrong

Sun Maung Oo

@nwp, well your hunch is better than mine since I am beginner on C++ stuff

nwp

> mpv_opengl_cb_context: Opaque context, returned by mpv_get_sub_api(MPV_SUB_API_OPENGL_CB)

Sun Maung Oo

8:02 PM

which mean?

nwp

looks like you need to get a valid context from mpv_get_sub_api before you can pass context to mpv_opengl_cb_init_gl

currently you are passing an invalid context. As far as I can see you never set it to anything.

Sun Maung Oo

Same problem

postimg.org/image/w2sbokk9z

Sun Maung Oo

8:19 PM

I think I know now where the error it

Is there any way to +rep you since you really help me a lot

nwp

no, its ok

Sun Maung Oo

no, I insist

I am going to logout now

bye and thank for all your help

nwp

well you can't SO doesn't allow it

cya

sehe

9:37 PM

@SunMaungOo what the hell is that site name. I'm not at all sure you're not actually (purposely or not) spreading malware here.

Posting links to binaries is rarely a very good idea and anyone who downloads from there without some form of authentication/outside trust is not very smart in my book.

← 1 message moved from Lounge<C++>

← 11 messages moved from Lounge<C++>

Sun Maung Oo

9:52 PM

@sehe, Thank for your advice.
I am not spreading a malware here.
If I look like I am spreading a malware, I apologize.
The binary (library) are the used for video playback.
The link to the library can easily are searchable by"Google".
I think the author (not me) of the library will not care if his library is known.
I usually password protected if I need to share something privately (thank for the advice anyway)

The link I provided can be find by tracing it back by github (github.com/cmdrkotori/mpc-qt) (if you have any doubt that it is a malware)

It is a hyper link (mpv windows release page)

sehe

10:17 PM

In case it wasn't clear, I don't care whether it /is/ malware. I'm telling you it's questionable conduct to come into a room as a stranger and post links like that. (And pointed out why). Peace

@SunMaungOo Thanks for explaining though. I didn't report you or anything. :)

Sun Maung Oo

@Se

@sehe , I will be more careful

have a good night or morning

Transcript for

Room for nwp and Sun Maung Oo