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swiftxcodemacosswift5ftdi

FTDI D2XX API in C works on command-line console but always returns zero in application which is built by Xcode and Swift programming on macOS

I'm trying to build an macOS application on masOS to communicate with FTDI D2XX device. I used gcc to compile a simple console app with C code and it works well and get expected device count. But when I tried to import the FTDI into Xcode and built an application with Swift 5. The application can be built and executed successfully but it always return 0 for FTDI device count. I tried to use two methods to import FTDI D2XX static library (ftd2xx.a) into Xcode. But both of them have same results.

  1. Created C wrapper and bridging header for calling FTDI D2XX API
  2. Created module and use “import xxx”

The C code to call FTDI D2XX API is:

int queryDeviceCount(void)
{
     FT_STATUS         ftStatus;
     DWORD             numDevs = 999;

     ftStatus = FT_CreateDeviceInfoList(&numDevs);
     if (ftStatus == FT_OK) {
           return numDevs;
     }

     return 0;
}

When FT_CreateDeviceInfoList is called, it returned FT_OK in ftStatus. But the numDevs is always zero (it should get 2 in my setup). I think the FTDI D2XX driver should be OK in my MacBookPro because it works well in command-line console. So, I'm wondering is there any difference in calling FTDI API between command-line console and GUI application. I'm pretty sure that the FTDI API is called correctly in GUI application.

Thanks!

Solution

  • I found in macOS GUI App, the system resource is protected. I need to enable the USB access ability in "App Sandbox" to use USB access APIs. App Sandbox appears in the Signing & Capabilities pane of Xcode revealing additional controls to configure the capability. USB access in App Sandbox