# VB Decompiler Plugin API: Developer Guide & SDK Reference > Official VB Decompiler Plugin API documentation. Learn how to build custom extensions, access internal structures, and automate decompilation tasks using the plugin engine. Canonical HTML: ## VB Decompiler Plugin API This documentation describes the interface for creating plugins for VB Decompiler. The plugin system allows you to analyze, modify, or extend the decompiled code and internal structures of the application via a shared library (DLL). 1. Architecture Overview The plugin system operates on a callback model: - VB Decompiler loads your DLL plugin. - It calls your exported functions to retrieve the plugin name and author info. - It calls VBDecompilerPluginLoad, passing a pointer to its internal **Callback Engine**. - Your plugin interacts with the host by calling this Engine function using specific Action IDs (vlType constants). 2. Exported Functions Your DLL must export the following stdcall functions: VBDecompilerPluginName Called by the host to retrieve the display name of your plugin. void __stdcall VBDecompilerPluginName( HWND VBDecompilerHWND, // Handle to main window HWND RichTextBoxHWND, // Handle to the code editor window char* Buffer, // Target buffer (100 bytes, ANSI) int Reserved // Reserved ); *Usage:* Copy a standard ASCII string (max 100 chars) with your plugin name into Buffer. VBDecompilerPluginAuthor Called to retrieve author contact information. void __stdcall VBDecompilerPluginAuthor( HWND VBDecompilerHWND, HWND RichTextBoxHWND, char* Buffer, // Target buffer (ANSI) int Reserved ); *Usage:* Copy a string like "Author Name, email@domain.com" into Buffer. VBDecompilerPluginLoad The main entry point where your plugin logic is executed. void __stdcall VBDecompilerPluginLoad( HWND VBDecompilerHWND, HWND RichTextBoxHWND, char* Buffer, // Reserved/Buffer void* PluginEngine // <--- Pointer to the Callback Function ); *Usage:* Store the PluginEngine pointer. You will use it to invoke GetValue / SetValue commands (see "Callback Engine" below). 3. The Callback Engine Communication with VB Decompiler is handled via a single callback function pointer provided in PluginEngine. **Function Signature:** typedef wchar_t* (__stdcall *TVBDPluginEngine)( int vlType, // Command ID (Action) int vlNumber, // Primary Index (Form/Module ID) int vlFnNumber, // Secondary Index (Function ID) char* vlNewValue // Value to set (ANSI string) or NULL for Get commands ); **Note:** The engine accepts ANSI strings (char*) for inputs but returns Unicode strings (wchar_t*) for results. 4. Command Reference (vlType) The following constants are used as the vlType argument to perform specific actions. Global Project Commands Operations related to the project file or global settings. vlNumber and vlFnNumber are usually 0. ID Constant Description 1 GetVBProject Get the full text of the decompiled project file. 2 SetVBProject Replace the project file content. 3 GetFileName Get the full path of the file being analyzed. (v3.5+) 4 IsNativeCompilation Returns "1" if the target is compiled to Native Code, "0" for P-Code. (v3.5+) 5 ClearAllBuffers Clears internal decompiler structures. Use this if your plugin implements a full custom decompiler for a new language. (v3.9+) 6 GetCompiler Returns compiler type: 1=VB, 2=.NET, 3=Delphi, 4=Unknown. (v3.9+) 7 IsPacked Returns "1" if the file is packed/compressed, "0" otherwise. (v3.9+) 56 GetVBDecompilerPath Returns the path to the VB Decompiler executable. (v3.5+) 100 UpdateAll Commit changes and refresh the GUI. **Required** after setting values to ensure the user sees changes. UI Control Control elements of the VB Decompiler interface. ID Constant Description 8 SetStackCheckBoxValue Set **Parse stack parameters** checkbox state. "1" = Checked, "0" = Unchecked. (v3.9+) 9 SetAnalyzerCheckBoxValue Set **Procedure analyzer and optimizer** checkbox state. "1" = Checked, "0" = Unchecked. (v3.9+) 50 GetActiveText Get text currently displayed in the active code window. 51 SetActiveText Set text in the active code window. 52 GetActiveDisasmText Get the raw disassembly text of the disassembler window. (v9.4+) 53 SetActiveDisasmText Set the raw disassembly text to the disassembler window. (v9.4+) 54 SetActiveTextLine Scroll or jump to a specific line number (passed as string in vlNewValue). 55 GetActiveModuleCoordinats Get IDs of the active view. Likely returns format "ModuleIndex,FunctionIndex". (v3.5+) 58 SetStatusBarText Display a custom message in the application status bar. (v3.5+) Forms Operations on VB Forms. vlNumber: Form Index (0-based). ID Constant Description 10 GetVBFormName Get the name of the form. 11 SetVBFormName Rename the form. 12 GetVBForm Get the decompiled properties of the form. 13 SetVBForm Set the properties of the form. 14 GetVBFormCount Returns total number of forms in the project. Modules Operations on Standard Modules (.bas) or Class Modules (.cls). vlNumber: Module Index (0-based). ID Constant Description 30 GetModuleName Get the name of the module. 31 SetModuleName Rename the module. 32 GetModule Get the decompiled declarations header of the module. 33 SetModule Set the decompiled declarations header of the module. 34 GetModuleStringReferences Get list of string references used in this module. 35 SetModuleStringReferences Set string references. 36 GetModuleCount Returns total number of modules. Procedures / Functions Operations on specific functions within a module. vlNumber: Module Index. vlFnNumber: Function Index (0-based) within that module. ID Constant Description 20 GetSubMain Get the code for the entry point (Sub Main). (Index args ignored). 21 SetSubMain Set the code for the entry point. 40 GetModuleFunctionName Get the name of a specific function. 41 SetModuleFunctionName Rename the function. 42 GetModuleFunctionAddress Get the memory address (VA) of the function. 43 SetModuleFunctionAddress Set the function address. 44 GetModuleFunction Get the decompiled code of the function. 45 SetModuleFunction Set the code of the function. 46 GetModuleFunctionStrRef Get string references specific to this function. 47 SetModuleFunctionStrRef Set string references for this function. 48 GetModuleFunctionCount Returns number of functions in the specified module. 57 GetModuleFunctionCode Get function code in "Fast Decompilation" mode (if this function is not processed at this time). (v3.5+) 70 GetModuleFunctionDisasm Get the disassembly (ASM) of the function. (v9.4+) 71 SetModuleFunctionDisasm Set the disassembly of the function. (v9.4+) Resources (FRX) Access to binary form resources (icons/images). vlNumber: Icon Index. ID Constant Description 60 GetFrxIconCount Returns total number of icons/images in FRX. (v5.0+) 61 GetFrxIconOffset Get the file offset for the specific icon. (v5.0+) 62 GetFrxIconSize Get the size (in bytes) of the specific icon. (v5.0+) Want to create your own plugin? Look at [Plugin Developer Guide](https://www.vb-decompiler.org/plugins_sdk.htm) and [Download the Plugin SDK](https://www.vb-decompiler.org/files/vb_decompiler_plugins_sdk.zip) [VB Decompiler Plugin SDK on GitHub](https://github.com/DotFixSoft)