using curl in a win c++ application - c++

I'm trying to use curl from within my windows c++ app but keep running into problems.
I'm using visual studio 2013 on a windows 8.1 machine.
Here's what I've done so far:
Cloned the repo from github
Built the libcurl project which produced three files: libcurl.dll, libcurl_imp.lib and libcurl_imp.exp
In my app project I added the curl include directory to the Additional Include Directories
Added the libcurl_imp.lib to the Additional Dependencies
Built my project
When I run my executable it says:
the program can't start because libcurl.dll is missing from your computer
I found a few things on it, but they solved it by adding the libcurl dll along with the exe, which isn't what I'm looking for as I want my executable to contain the libcurl so that it will work on machines without the need to have the dll.
Any ideas?
Thanks.
Edit
The 2nd step is done pretty much straight forward, I just right clicked on the project (libcurl) and chose buiild.
Due to the comments I've rebuilt it after changing the Configuration Type to Static library, so now it only produces one file: libcurl.dll which, as far as I know not a static library...
2nd edit
I wasted too much time on getting http functionality, and based on the info which I found thanks to a comment here (using libcurl without dll) I've decided to abandon this approach, and I found something which suits my needs perfectly and is simple to install/use: C++ REST SDK (codename "Casablanca")

Try to add libcurl.dll directory to PATH environment variable.

Related

Missing libgcc_s_seh-1.dll starting the .exe on Windows

Intro
I have a CMake-based C++ project. Until now I build and ran the project via CLion. Everything worked fine until I tried to run the .exe-file directly (not via CLion).
Problem
When I navigate to the cmake build directory in order to start my program via the executable file, it fails with the following message in the popup: Cannot continue the code execution because libgcc_s so-1.dll was not found. Reinstalling the program may resolve the issue.
I have the following questions
If I interpret the error message correctly, then this dll is missing on my computer. So I ask myself, why does my program still work when I start it via the development environment (CLion), although the error message expressly states that the source code requires this dll?
Is it the fault of my application/source code that the error appears or rather the current state of my computer? If the former, how can I prevent this error from appearing for other users?
What is the best way to fix this error? It's obvious that I need to download this dll, but where is the best place to put it (which directory and environment variable to use on Window)?
Which source is trustworthy to download this dll? I don't want to download any malware under this dll-name.
Optional: What kind of library is that? What functionalities does it offer?
Additional information
I use CMake as my build tool, CLion as the IDE and MinGW as the compiler.
What I have did so far?
I made sure it still works through the IDE.
I found this dll does not exist in the MinGW installation folder.
I searched the web for more information. Unfortunately, there are only pages unknown to me that only offer the download of this dll. That doesn't satisfy me.
I found the cause of my problem: I had two MingGW installations on my machine. Once the installation that comes with CLion and a separate one. The latter did not have the required dll. However, CLion used its own installation, which in turn owns the DLL. So the solution was to remove the separate installation and include the path to the CLion installation's bin/ directory in the PATH environment variable.
This file is part of MinGW-w64 when using SEH as exception model (as opposed to Dwarf or SJLJ). You need to distribute the .dll files your .exe file(s) depend on in the same folder as the .exe file(s).
If you don't have that file, then you probably have been using libraries compiled with different versions of GCC/MinGW(-w64). I recommend building everything with the same compiler to ensure stable binaries.
Tools like Dependency Walker can help you figure out which .dll files your .exe file depends on.
Or use the command line tool copypedeps -r from https://github.com/brechtsanders/pedeps to copy the .exe files along with it's dependencies.

Qt-Application Deployment doesn't work. Missing entry point and dll's

In the last months I created a project with the Qt-Creator version 4.7.0, Qt version 5.11.1 (open source version).
Now I tried to deploy it following the Qt doc and building the project with MSVC2017-64bit compiler as well as running windeployqt.exe afterwards on the generated executable.
As I tried to run the executable after the programm finished copying the neccessary dlls into the folder, a warning appeared:
The entry point ?
eventFilter#QAbstractItemView##MEAA_NPEAVQObject##PEAVQEvent###Z wasn't found in DLL "my/project/path/releasefolder/project.exe".
It seems to me like something was wrong with the Qt-Objects I use in my project, but I couldn't find anything, as it still worked flawlessly in the Qt-Creator.
A thought it might be due to the compiler having issues, so I changed it to mingw32, which I also tried to deploy the same way. But somehow in this case the warning disappeared, but many dlls were still missing even though windeployqt.exe should've already done that. And I also couldn't find them anywhere on my hard drive. I also tried a third compiler, but the issues weren't going away.
I searched online and only found people having problems with an entry point missing in a Qt dll or missing the Qt-Dlls in general, but haven't found anything related to my case.
I also tried Dependency Walker on every executable, but it found even more missing dll, which led me to believe the executables were somehow currupted so I tried it again and again, but with no success unfortunately.
Has someone any idea, why that could happen, or any suggestion for me?
Maybe I should change something in my project, even though it works fine in the IDE. I just need a way to deploy my Qt project in any way.
EDIT: Build using the Desktop Kit in Qt Creator with MSVC2017 the described warning appeared.
Build with Mingw32 (Desktop Kit) and with MSVC2017 using the UWP Kit in Qt Creator the following Dll was missing, that I haven't found anywhere on my hard drive: MSVCP140_APP.dll
EDIT2: I ended up downloading the required dll, to somehow get it to work, but it still didn't work. One build, that required that dll now started but immediately closes itself again and the other build was suddenly warning me of a missing procedure entry point.
EDIT [SOLUTION]: I let the Qt Creator create a whole new fresh project and copied all files from my old project in the new one. After that I only copied all the dll files into the folder and it worked.
Instead of relying on windeploy, manually add the dll. I am assuming you have built the project using mingw. Assuming you are using Qt 5.11.1, go to
C:\Qt\Qt5.11.1\5.11.1\\bin\ and copy all the dll files and paste in your executable folder. Also copy all directories from plugins folder (in /plugins) and paste in your folder. Now run the application, don't close the application. Now delete all the files from your executable folder. The one's not being used are deleted and the rest are left. I assume you are doing this on target computer. This might help.

Linking libjpeg to an xCode project for iOS dev

Good evening,
I have been working on a C++ project from someone of my University which I had to improve for my Bachelor thesis. It basically uses the library libjpeg to do some computation resulting in a steganographic process in order to embed a message into a given image.
Now that the C++ code works smoothly, I'd like to create a little iOS app allowing the user to encrypt whatever message he'd like into an image of his choice. So I created an xCode project following this procedure: using c++ in an iOS app
I also found the following file: libjpeg for iOS which allowed me to compile libjpeg for iOS. Since I'm not so sure how to use the framework freshly created and couldn't find anything sufficiently convincing on the internet, I put all the files (.c and .h) of the libjpeg library into my "include" folder where I have my own .hpp.
xCode only throws me the following error:
xCode error
From what I could gather on several posts, I have to modify the build options of my xCode project to link manually the library, so I tried the following:
Other linking flags
Library search path
This wasn't enough to do the trick and I'm still struggling with the same error xCode throws at me. Any help would be very appreciated on how to proceed!
Thanks a lot,
Theo.
Do not add the .c files to your project, add the libjpeg.a file produced by your build to your project. Add the .h files as you are already doing, or edit the project settings to include their containing folder in the search path.
HTH

Application error - debug exe wont run

I've recently downloaded Assimp and I've run into some troubles.
I've linked the libraries and I can get the program to compile and it runs fine in Release mode; however, the Debug .exe hits me with this error:
The application was unable to start correctly (0xc0150002). Click OK to close the application.
Some more details:
I'm using VS2010 with Target Machine set to x86.
I am using the 32bit debug dll (Assimp32d.dll) that was provided, and I've tried setting runtime libraries to /MT, /MTd, /MD, and /MDd with no luck.
I read from other similar threads that I should run Dependency Walker on the .exe, but I'm not sure what the output means. I'll paste it here if this helps you guys.
Error: The Side-by-Side configuration information for "c:\users\-----\documents\visual studio 2010\projects\AssimpTest\debug\ASSIMP32D.DLL" contains errors. The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail (14001).
Error: At least one required implicit or forwarded dependency was not found.
Error: At least one module has an unresolved import due to a missing export function in an implicitly dependent module.
Error: Modules with different CPU types were found.
Rather than rebuilding the libraries, I downloaded a different set of libraries (it was the SDK installer) and the debug dll's from that are working perfectly.
Just in case anyone has the same problem with the same software, this was the exact name of the installer that worked for me: assimp-sdk-3.0-setup.exe
I ran into the same problem when trying to run a 64-bit project in Debug mode when using Assimp 3.0.
What I did was go to assimp/workspaces/vc9, open assimp.sln in Visual Studio 10, convert the project, then rebuild the 32 and 64-bit dll.
Mind you, you've got to install boost for that as well, and edit the project properties so it points to the boost directory for includes.
There's probably a way to do it using CMake as well, but I found the whole process too cumbersome to bother with in the first place.
My solution was just to link the debug build to the release .dll files. No more issues, and I wasn't that interested in debugging the Assimp library anyway!
I faced the same issue, later on I downloaded the "assimp-sdk-3.0-setup.exe" file & installed it as a standard windows application.
I pointed Visual Studio Solution Include & Lib directories to respective folders from newly installed location, copied DLL to my application location. The problem was resolved. Hope this helps someone.
Cheers.

Using a DLL with unmanaged code in Visual Studio 2010?

I'm fairly new to C++ and an trying to figure out to use the TagLib library for a project I am working on. I'm working with unmanaged C++ in Visual Studio 2010 on Windows 7 64bit. I've never used an external library before so I'm very confused on how to go about this.
From this blog entry I got the libtaglib.a and taglib.dll files. I ran across this SO question on how to use TagLib, but it deals with QT Creator, not Visual Studio and I'm not knowledgeable enough about the subject to understand what is being said to translate it into what needs done for Visual Studio.
So, some questions:
Is it even possible to do this with unmanaged code?
What exactly is the function of a .a file?
Most importantly, how do I go about using the taglib.dll in my program??
I've been all over Google looking for a way to do this, but my major problem is that everything I run across is over my head. Please let me know if more info is required. Any help is very much appreciated! Thanks!
I seem to have gotten it working successfully. Here's a rough outline of what I did:
1.) I used CMake to generate the Visual Studio solution.
2.) I attempted to build the tag project in the VS solution, but it failed.
3.) I made the corrections to a few source files as outlined here: http://old.nabble.com/taglib-fails-to-compile-with-MS-VC%2B%2B-2010-td29185593.html
4.) I built the tag project again in release mode. This time it was successful.
5.) I copied the resulting dll, def, and lib files to the same directory as the source files for my project.
6.) I copied the header files from the taglib source to a subdirectory in my project (not sure if this entirely good practice)
7.) In my project settings, I set the subdirectory with the header files as an additional include directory.
8.) I added the dll, exp, and lib files to my project by just going to Add>Existing Item.
9.) I added some code from the taglib examples and built it. Everything worked so I think I got it.
One caveat I ran into, since the DLL was built in release mode, my project had to be run in release mode or it would crash. I'm guessing that if I replaced the DLL with one built in debug mode I could run my program in debug mode, but I have not tried this.
You cannot use libraries specific to GCC (you can tell because they have .a extensions) with Visual Studio. You will have to build the library from source in order to use it with MSVC. Once you have done that it's a simple matter of adding the .lib generated from the build process to your project and things should work out of the box. (Note that it's a .lib you need whether you're compiling for dynamic linking or not -- doesn't matter in msvc land)
EDIT -- after looking at TagLib itself --
In order to compile TagLib you'll need to get the CMake build system, and TagLib itself, and have CMake build you a visual studio solution. Using that solution you'll be able to build the .libs and .dlls you need. Note that because TagLib is a KDE library, you'll probably need to also build some QT bits in order for everything work work successfully. However, I don't have specific experience with the library so I'm not going to be all that helpful here.
Yo do not have to recompile the source (to create the .lib file) if you have the .dll file. With dumpbin /exports and lib (both came with Visual Studio) yo can create a lib that you can link with your application. In this link you can see a nice explanation: http://www.coderetard.com/2009/01/21/generate-a-lib-from-a-dll-with-visual-studio/
But as Billy Said, probably you would need other parts of QT to use this library.