/// <summary>
/// gets the address of a symbol (function or global variable) from an unmanaged library
/// </summary>
/// <param name="SymbName"></param>
/// <summary>
/// releases a dynamic library
/// </summary>
/// <param name="libHandle">
/// handle, which was acquired by <see cref="LoadDynLib"/>
/// </param>
/// <returns>
/// a function/symbol pointer;<br/>
/// using the function <see cref="System.Runtime.InteropServices.Marshal.GetDelegateForFunctionPointer"/>
/// it can be converted to a .NET delegate.
/// </returns>
/// <remarks>
/// On Windows, this function redirects to the 'GetProcAddress'-function in kernel32.dll;<br/>
/// On Unix, this function redirects to the 'dlsym'-function in libdl.so;
/// </remarks>
/// <param name="errstr">
/// on success, null;
/// if call failed (return value is null), an error information provided by the operating system
/// </param>
public static IntPtr LoadSymbol(DynLibHandle libHandle, string SymbName, out string errstr)
{
PlatformID plattid = System.Environment.OSVersion.Platform;
IntPtr ret;
errstr = null;
Debug.Assert(Marshal.SizeOf(typeof(DynLibHandle)) == IntPtr.Size, "runtime created struct of wrong size.");
switch (plattid)
{
case PlatformID.Win32NT:
ret = GetProcAddress(libHandle, SymbName);
if (ret == IntPtr.Zero)
{
errstr = GetLastWin32Error();
}
return(ret);
case PlatformID.Unix:
//Console.WriteLine("Trying to load >" + SymbName + "< form lib >" + libHandle.val + "< ...");
ret = dlsym(libHandle, SymbName);
if (ret == IntPtr.Zero)
{
errstr = _dlerror();
}
return(ret);
default:
throw new NotImplementedException("Symbol Loading for " + plattid + " is not supported.");
}
}
/// <summary>
/// releases a dynamic library
/// </summary>
/// <param name="libHandle">
/// handle, which was acquired by <see cref="LoadDynLib"/>
/// </param>
/// <remarks>
/// On Windows, this function calls the 'FreeLibrary'-function in kernel32.dll;<br/>
/// On Unix, this function calls the 'dlclose'-function in libdl.so;
/// </remarks>
public static void UnloadDynLib(DynLibHandle libHandle)
{
PlatformID plattid = System.Environment.OSVersion.Platform;
switch (plattid)
{
case PlatformID.Win32NT:
FreeLibrary(libHandle);
break;
case PlatformID.Unix:
dlclose(libHandle);
break;
default:
throw new NotImplementedException("Dynamic Library Release for " + plattid + " is not supported.");
}
}
static extern int dlclose(DynLibHandle handle);
static extern IntPtr GetProcAddress(DynLibHandle hModule, [MarshalAsAttribute(UnmanagedType.LPStr)] string lpProcName);
unsafe static extern IntPtr dlsym(DynLibHandle handle, string symbol);
static extern bool FreeLibrary([InAttribute()] DynLibHandle hModule);
