C++ Builder 10.3 Rio 亚马逊存储服务示例

Question

I am trying to move an application that uses C++Builder's TAmazonConnectionInfo to access objects on Amazon Simple Storage Service (S3). I had a version working in C++Builder 10.1 Berlin, but when I try to move it to 10.3 Rio, the link fails with an Unresolved external error:

[ilink32 Error] Error: Unresolved external '__fastcall Data::Cloud::Amazonapi::TAmazonStorageService::GetObjectW(System::UnicodeString, System::UnicodeString, System::Classes::TStream *, Data::Cloud::Cloudapi::TCloudResponseInfo *, Data::Cloud::Amazonapi::TAmazonRegion)'

The simplest reproduction of this error is:

1. Create a new C++ Builder VCL Application
2. Place a TAmazonConnectionInfo object and a button on the form and double-click the button

3. Replace the click handler with:

    void __fastcall TForm1::Button1Click(TObject *Sender) { TCloudResponseInfo * ResponseInfo = NULL; TAmazonStorageService *StorageService = NULL; TStream* stream; String ObjectName; StorageService->GetObject(ObjectName, ObjectName, stream, ResponseInfo); }

(I realize that this routine won't work because nothing is initialized, but this will produce the link error with the least amount of code).

I looked for a code sample showing how this should work, but I cannot locate the code samples for RAD Studio 10.3 Rio on my system, and it does not appear that the samples have been updated for Rio on the RAD Studio Demo Code on SourceForge.

I did find the samples on Github at https://github.com/Embarcadero/RADStudio10.3Demos/tree/master/CPP , but the Cloud samples do not appear to have been migrated for C++ Builder, only for Object Pascal.

I tried adding CloudService.lib to the project, but that did not help. Neither did adding:

#pragma link "Data.Cloud.CloudAPI"
#pragma link "Data.Cloud.AmazonAPI"

So, is there a working C++Builder sample that compiles and links under 10.3 Rio? How can I get this project to compile and link?

Answer 1

The problem is that the Data.Cloud.AmazonAPI.hpp header includes internally the wingdi.h Windows API header. This header has a macro that replaces GetObject for GetObjectA/W .

The workaround I managed to get working was to add the following to the Data.Cloud.AmazonAPI.hpp header, just below where the #includes end (around line 27):

#pragma push_macro("GetObject")
#undef GetObject

Then, at the end of the header, just before the #pragma delphiheader end. (around line 897) add the following:

#pragma pop_macro("GetObject")

This solves the headers issue, but you still have to add this around the code where you want to use that function so it compiles, otherwise it is going to try to compile GetObjectW that now doesn't exists at compile time.

Answer 2

I had the same problem. I just tested this solution, it works! Thank you!

You must copy the file to the desktop in order to be able to modify it, then recopy it in the installation directory.

I add that it is necessary to initialize the property "Storage EndPoint" of the TAmazonConnectInfo component with the name of the EndPoint that you must create from your Bucket