I am currently using SOCI with SQLite3. Everything was working fine until I got to the point that I needed to call a native SQLite3 function in order to enable loading custom extensions into my database (http://www.sqlite.org/loadext.html). Here is the code I am using:
sqlite3_session_backend* backend;
backend = static_cast<sqlite3_session_backend *>(databaseSession.get_backend());
sqlite_api::sqlite3* db = backend->conn_;
sqlite_api::sqlite3_enable_load_extension(db, 1);
It gives me a segmentation fault at runtime when it reaches the last line of code. I have used a debugger to check if the pointer the backend is returning is valid, and it is. I have also tried calling other native SQLite3 API functions, and they all result in segmentation fault. What am I missing here? These are the includes in my code:
#include <soci.h>
#include <soci-sqlite3.h>
I have also tried to include sqlite3.h, but it gives the same result. I am using clang++. Any ideas?
Related
So, I want SQL errors to prevent C++ code from building successfully.
What I was thinking was compiling via some cmake script or something that would grep the cpp files for SQL and validate the SQL.
I know I could add some kind of runtime error checking but I don't want the following code to build sucessfully (not a question about pqxx, but SQL errors in C++ in general):
#include <iostream>
#include <pqxx/pqxx>
using namespace std;
using namespace pqxx;
int main() {
connection conn("dbname=d user=u");
conn.prepare("invalid_sql", "SELECT 1 FROM WHERE a = $1");
nontransaction txn(conn);
txn.prepared("invalid_sql")(1.0).exec();
cout << "the process already died due to invalid SQL" << endl;
return 0;
}
You can, sort-of...
One approach is Boost meta_parsing, another is using C++11's user-defined literal types. I couldn't find a worked example for SQL, but perhaps as C++11 matures someone will come up with one.
Closing this question. The other answer is fine, but that's not what I did.
What I decided to do was put the prepared statements in a init_sql() method and call that using boost/test/unit_test.hpp against a replicated database with jenkins, which provides notifications for unit test failures.
I am new to C++ (was previously into Java) and I am trying to find my way around it for the past few days. I am having a Sqlite DB in my local Machine which I am trying to access in order to display the results of a query on a Windows Application Form using DataGridView.
I was able to locate a good place to start here but later discovered that this was more concentrated towards SQL server and not SQLite and the code failed when I tried to replace this part of code
String^ connectionString =
"Integrated Security=SSPI;Persist Security Info=False;" +
"Initial Catalog=Northwind;Data Source=localhost";
with this
String^ connectionString = "Data Source=C:\\data\\test.db"
to point to my local Sqlite DB (test.db).
Upon more digging I found that I was able to find C# examples for linking SQLite DB to Windows Form Application here. Next I tried to convert the C# code provided into a C++ one but failed.
I have been looking all around for simple C++ examples which would help me understand how to link a Sqlite DB to a Windows Form Application but am not able to do so yet.
I would appreciate it greatly if anyone could point me to one such example.
To access SQLite DB from managed code use System.Data.SQLite library. It's a managed library supported by SQLite Development Team and you can use it with managed C++ also. Here is the sample:
using namespace System::Data::SQLite;
using namespace System::Text;
void Test()
{
SQLiteConnection ^db = gcnew SQLiteConnection();
try
{
db->ConnectionString = "Data Source=C:\\data\\test.db";
db->Open();
// Do the job here
db->Close();
}
finally
{
delete (IDisposable^)db;
}
}
I have read this blogpost http://www.ics.com/blog/qt-tips-and-tricks-part-1 and tried to enable plugin debugging as described.
I've put this line in my main.cpp:
qputenv(QT_DEBUG_PLUGINS, 1);
But if I try to compile I'm getting this error:
.../src/main.cpp:14: error: 'QT_DEBUG_PLUGINS' was not declared in this scope
qputenv(QT_DEBUG_PLUGINS, -1);
What is the problem here and how do I have to do it right?
qputenv("QT_DEBUG_PLUGINS", QByteArray("1"));
But I don't get any additional output.
I'm using Qt5.5.1 with QtCreator 3.6 under KUbuntu 15.10.
You're supposed to set env variable from outside your program, not from inside! It's very likely the plugin loading you're interested into already happened by the time you reach that line. Try putting it before creating a Q*Application object.
– peppe
That's it. It was definitely set before plugin loading, but it seems to be important to set it before creating Q*Application as you wrote. Thank you.
– avb
I am trying to use SVNKit to get a Log of the SVN Entries in Coldfusion. I downloaded the latest SVNKit jar files and threw them in the lib folder under WEB-INF/lib.
Here is my code that should return an Array Of Log Entries but this code is returning a Null Pointer exception in Coldfusion 9.0.2.
SVNURL = createObject('java','org.tmatesoft.svn.core.SVNURL').parseURIEncoded(svnurl);
drf = createObject("java","org.tmatesoft.svn.core.internal.io.dav.DAVRepositoryFactory");
drf.setup();
rf = drf.create(SVNURL);
SVNWCUtil = createObject("java","org.tmatesoft.svn.core.wc.SVNWCUtil");
authManager = SVNWCUtil.createDefaultAuthenticationManager(user,pass);
rf.setAuthenticationManager(authManager);
log = rf.log(JavaCast("String[]",[]),JavaCast("null",""),JavaCast("long",10),JavaCast("long",15),true,true);
rf.closeSession();
When running this code, I receive the following Error.
The system has attempted to use an undefined value, which usually indicates a programming error, either in your code or some system code.
Null Pointers are another name for undefined values.
Which points to this line..
log = rf.log(JavaCast("String[]",[]),JavaCast("null",""),JavaCast("long",10),JavaCast("long",15),true,true);
I moved this same code over to Railo, and everything is running fine. I just cannot see why ACF is choking on the log() method.
I was using the Printing Out Repository History example on the SVNKit Wiki to start me off.
Any suggestions on getting it to work in Adobe Coldfusion would be greatly appreciated. I did not test on CF10.
I wasn't using the JavaCast("boolean",true) for the last two arguments in the log() function. After that, everything worked fine.
Got to remember to check and use JavaCast()!
log = rf.log(JavaCast("String[]",[]),JavaCast("null",""),JavaCast("long",10),JavaCast("long",15),JavaCast("boolean",true),JavaCast("boolean",true));
The explanation of the problem is a little long-winded, please bear with me.
I have an unmanaged C++ static library that is used for financial application. It has business day conventions, swap conventions, bond conventions, etc. Most of the conventions rely on static global variables, which are initialized on first use. The library also initializes the holiday calendars on startup by running some queries against a SQL Server database using ODBC.
I have to interact with third-party software using web services. The only way to do this realistically is through C#. That isn't an issue, and I was making good progress. However, I hit a stumbling block when it became necessary to do some date calculations in C#. Since I didn't want to port all my C++ code to C#, I figured the most efficient way to achieve this would be by writing a Managed C++ Class Library DLL that is a wrapper around my unmanaged static library. Everything seems to work fine, I get no compile-time or link-time errors, and I can add the reference to the wrapper and see all the proper object definitions. However, when I try to run my application, it just hangs. I have tried playing around with a bunch of compiler setting for the wrapper DLL, to no avail. If I remove the project dependency on my unmanaged library, everything works fine. I have a strong suspicion that my liberal use of global static variables is causing issues. Is there are way to solve this problem, are at least figure out where the issue is? Example code is below.
Thanks,
Marc.
// FSAManaged.h
#pragma once
using namespace System;
//class XLDate;
namespace FSAManaged {
public ref class Futures
{
public:
static DateTime Expiry(String ^ code, DateTime date);
};
}
The implementation does not even rely on a dependency to the unmanaged static library:
// This is the main DLL file.
#include "stdafx.h"
#include "FSAManaged.h"
namespace FSAManaged
{
DateTime Futures::Expiry(String ^ code, DateTime date) {
return DateTime::Today;
}
}
For completeness' sake, here is AssemblyInfo.cpp:
#include "stdafx.h"
using namespace System;
using namespace System::Reflection;
using namespace System::Runtime::CompilerServices;
using namespace System::Runtime::InteropServices;
using namespace System::Security::Permissions;
//
// General Information about an assembly is controlled through the following
// set of attributes. Change these attribute values to modify the information
// associated with an assembly.
//
[assembly:AssemblyTitleAttribute("FSAManaged")];
[assembly:AssemblyDescriptionAttribute("")];
[assembly:AssemblyConfigurationAttribute("")];
[assembly:AssemblyCompanyAttribute("?????")];
[assembly:AssemblyProductAttribute("FSAManaged")];
[assembly:AssemblyCopyrightAttribute("??????")];
[assembly:AssemblyTrademarkAttribute("")];
[assembly:AssemblyCultureAttribute("")];
//
// Version information for an assembly consists of the following four values:
//
// Major Version
// Minor Version
// Build Number
// Revision
//
// You can specify all the value or you can default the Revision and Build Numbers
// by using the '*' as shown below:
[assembly:AssemblyVersionAttribute("1.0.*")];
[assembly:ComVisible(false)];
[assembly:CLSCompliantAttribute(true)];
[assembly:SecurityPermission(SecurityAction::RequestMinimum, UnmanagedCode = true)];
Use the debugger. If you test this from C# then Project + Properties, Debug, tick "Enabled unmanaged code debugging". Setting up the symbol server in Tools + Options, Debugging, Symbols is strongly recommended. Run.
When it hangs use Debug + Break All. Debug + Windows + Threads and double-click the thread that is supposed to be doing the job. Debug + Windows + Call stack to see what is going on. Post the stack trace in your question if you can't figure it out. Anything you see in the Output window and the Visual Studio status bar is relevant too.
Static C++ variables are initialized from DllMain. There are lot's of things you should not do in DllMain; triggering the load of yet another Dll being the most important one. This is easy to break if you call into other peoples libraries in from DllMain.
I suggest you make an Init function on your Dll, which you call after the dll is up and running.