System.Data.SQLite

        <tr valign="top">
          <td>Force_SQLiteLog</td>
          <td>If this environment variable is set [to anything], the SQLite
          logging subsystem may be initialized in a non-default application
          domain.  By default, this is not allowed due to the potential for
          application domain unloading issues.</td>
        </tr>
        <tr valign="top">
          <td>Initialize_SQLiteLog</td>
          <td>If this environment variable is set [to anything], the SQLite
          logging subsystem will attempt to perform initialization even when
          an attempt was previously made.</td>
        </tr>
        <tr valign="top">
          <td>No_PreLoadSQLite</td>
          <td>If this environment variable is set [to anything], the native
          library pre-loading code will be disabled.  By default, the native
          library pre-loading code will attempt to load the native SQLite
          library from architecture-specific (e.g. &quot;x86&quot;,
          &quot;amd64&quot;, &quot;x64&quot;) or platform-specific (e.g.

              logging subsystem may be initialized in a non-default application
              domain.  By default, this is not allowed due to the potential
              for application domain unloading issues.
    -->
    <!--
    <add key="Force_SQLiteLog" value="1" />
    -->

    <!--
        NOTE: If this environment variable is set [to anything], the SQLite
              logging subsystem will attempt to perform initialization even
              when an attempt was previously made.
    -->
    <!--
    <add key="Initialize_SQLiteLog" value="1" />
    -->

    <!--
        NOTE: If this configuration variable is set [to anything], the native
              library pre-loading functionality will be disabled.  By default,
              the native library pre-loading will attempt to load the native
              SQLite library from architecture-specific (e.g. "x86", "amd64",
              "x64") or platform-specific (e.g. "Win32") directories that

/********************************************************
 * ADO.NET 2.0 Data Provider for SQLite Version 3.X
 * Written by Robert Simpson (robert@blackcastlesoft.com)
 *
 * Released to the public domain, use at your own risk!
 ********************************************************/

namespace System.Data.SQLite
{
    using System;
    using System.Data.Common;
    using System.Diagnostics;
    using System.Globalization;
    using System.Threading;

    /// <summary>
    /// Event data for logging event handlers.
    /// </summary>
    public class LogEventArgs : EventArgs
    {
        /// <summary>

        /// The base SQLite object to interop with.
        /// </summary>
        private static SQLiteBase _sql;
#endif

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// This will be non-zero if an attempt was already made to initialize
        /// the (managed) logging subsystem.
        /// </summary>
        private static int _attemptedInitialize;

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// This will be non-zero if logging is currently enabled.
        /// </summary>
        private static bool _enabled;

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Initializes the SQLite logging facilities.
        /// </summary>
        public static void Initialize()
        {
            //
            // NOTE: First, check if the managed logging subsystem is always
            //       supposed to at least attempt to initialize itself.  In
            //       order to do this, several fairly complex steps must be
            //       taken, including calling a P/Invoke (interop) method;
            //       therefore, by default, attempt to perform these steps
            //       once.
            //
            if (UnsafeNativeMethods.GetSettingValue(
                    "Initialize_SQLiteLog", null) == null)
            {
                try
                {
                    if (Interlocked.Increment(ref _attemptedInitialize) > 0)
                    {
                        return;
                    }
                }
                finally
                {
                    Interlocked.Decrement(ref _attemptedInitialize);
                }
            }

            //
            // BUFXIX: We cannot initialize the logging interface if the SQLite
            //         core library has already been initialized anywhere in
            //         the process (see ticket [2ce0870fad]).
            //
            if (SQLite3.StaticIsInitialized())
                return;