OS. Initiate OpenSTAAD in C++

Note: You must have a model open in STAAD.Pro for this example. Otherwise your code will return an error.

Create and add a manifest file to your C++ project:

Create a new file and save it somewhere convenient with a .manifest file extension.
Right-click on your project from within Visual Studio and then select Add > Existing Item from the pop-up menu.
Browse to the manifest file and select it.

Open the manifest file and add the following contents:

XML

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
	<trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
		<security>
			<requestedPrivileges>
				<requestedExecutionLevel level="asInvoker" uiAccess="false"></requestedExecutionLevel>
			</requestedPrivileges>
		</security>
	</trustInfo>
	<comInterfaceExternalProxyStub name="IOSMemberSteelDgnParams" iid="{F40BDCDA-B3DE-495C-B84F-790F4456137F}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOpenSTAADUI" iid="{3F5B8055-31C6-446E-8BED-FEE43E09D4CC}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSGeometryUI" iid="{C052FED9-A2D6-42E3-A271-2C6FB8461711}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IStaadProWindow" iid="{9EF2FF8C-E574-4A04-9462-2E4500C8EADB}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSViewUI" iid="{87B1975B-6031-487E-A0F9-FB8F69FA24E6}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSOutputUI" iid="{824F1FC0-DC86-4CC4-A4C6-83C77D7B0496}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSPropertyUI" iid="{F919EF7D-E1DD-48CB-B3C3-B3CAE9E3B5AB}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSLoadUI" iid="{DAA37D16-821F-4137-88EB-DA4EB7650E90}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSTableUI" iid="{CF1A7B89-A007-4844-A098-CBABAEBEF304}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSSupportUI" iid="{B076EC62-9A33-4E1C-B38C-3E45090B8531}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSCommandsUI" iid="{6B994A7C-122C-4828-B42B-1B0CADF91F9D}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
	<comInterfaceExternalProxyStub name="IOSDesignUI" iid="{ED218322-40EE-411C-8552-209DB2C4F32B}" tlbid="{EDA9FA7F-EFC9-4264-9513-39CF6E72604D}" proxyStubClsid32="{00020420-0000-0000-C000-000000000046}"></comInterfaceExternalProxyStub>
</assembly>

Import the StaadPro.dll by typing: #import "C:\Program Files\Bentley\Engineering\STAAD.Pro 2026\STAAD\StaadPro.dll" named_guids and then press Return.
Set the namespace by typing namespace OSApp = OpenSTAADUI; and then press Return.
This namespace provides a wide variety of members that support COM interop and platform invoke services.
Place the cursor inside the int main().
Add the following lines:
```
OSApp::IOpenSTAADUIPtr OSAppPtr;
CoInitialize(NULL);
HRESULT hr = OSAppPtr.CreateInstance(__uuidof(OSApp::OpenSTAAD));
if (hr != S_OK)
	{
	printf("Unable to connect to STAAD.Pro application!\n");
	return 1;
	}

hr = OSAppPtr.GetActiveObject(__uuidof(OSApp::OpenSTAAD));
```
This initiates OpenSTAAD and connects to the current STAAD.Pro model to your program.
CreateInstance creates an uninitialized object and GetActiveObject retrieves a pointer to a running object that has been registered with OLE.

Your program at this point should look like:

C++

#import "C:\Program Files\Bentley\Engineering\STAAD.Pro
                    2026\STAAD\StaadPro.dll" named_guids
using namespace OpenSTAADUI;
using namespace std;
namespace OSApp = OpenSTAADUI;   
 
    int main()
{
	OSApp::IOpenSTAADUIPtr OSAppPtr;
		try
			{
			CoInitialize(NULL);
			HRESULT hr = OSAppPtr.CreateInstance(__uuidof(OSApp::OpenSTAAD));

			if (hr != S_OK)
				{
				printf("Unable to connect to STAAD.Pro application!\n");
				return 1;
				}

			hr = OSAppPtr.GetActiveObject(__uuidof(OSApp::OpenSTAAD));
			if (hr != S_OK)
			{
				printf("Unable to connect to an active instance of STAAD.Pro application!\n");
			return 1;
			}
}
catch (_com_error& e)
		{
		_bstr_t bstrDescription = e.Description();
		printf("COM Error! %s\n", bstrDescription);
		}
}