在 Windows 上使用带有 Golang 系统调用的结构？

Question

的EnumPrintersWin32函数需要和参数_Out_ LPBYTE  pPrinterEnum，一个指向分配的缓冲区。在 C 中，它是这样工作的：DWORD cbNeeded, nPrinters;EnumPrinters(PRINTER_ENUM_LOCAL, NULL, 5, NULL, 0, &cbNeeded, &nPrinters);BYTE *pPrnInfo = malloc(cbNeeded);EnumPrinters(PRINTER_ENUM_LOCAL, NULL, 5, pPrnInfo, cbNeeded, &cbNeeded, &nPrinters);PRINTER_INFO_5 *pPrinterInfo = (PRINTER_INFO_5 *) pPrnInfo;for (int i=0; i < nPrinters; i++) {  printf("pPrinterName: %s\n", pPrinterInfo[i].pPrinterName);}在 Go 中如何使用syscall而不是 cgo完成相同的操作？到目前为止，编译这么多，但我不知道如何将生成的字节切片转换为结构数组（不使用 cgo）。type PrinterInfo5 struct {    pPrinterName             *uint16    pPortName                *uint16    attributes               uint32    deviceNotSelectedTimeout uint32    transmissionRetryTimeout uint32}...dll := syscall.MustLoadDLL("winspool.drv")f := dll.MustFindProc("EnumPrintersW")var cbNeeded, nPrinters uint32fmt.Println(cbNeeded, nPrinters)f.Call(PRINTER_ENUM_LOCAL, 0, 5, 0, 0, uintptr(unsafe.Pointer(&cbNeeded)), uintptr(unsafe.Pointer(&nPrinters)))fmt.Println(cbNeeded, nPrinters)var pPrnInfo []byte = make([]byte, cbNeeded)f.Call(PRINTER_ENUM_LOCAL, 0, 5, uintptr(unsafe.Pointer(&pPrnInfo)), uintptr(cbNeeded), uintptr(unsafe.Pointer(&cbNeeded)), uintptr(unsafe.Pointer(&nPrinters)))我试过这个，它成功打印了一次迭代，然后失败了fatal error: heapBitsBulkBarrier: unaligned arguments：hdr := reflect.SliceHeader{  Data: uintptr(unsafe.Pointer(&pPrnInfo)),  Len:  int(nPrinters),  Cap:  int(nPrinters),}s := *(*[]PrinterInfo5)(unsafe.Pointer(&hdr))for _, t := range s {  fmt.Println(t)}

Answer 1

uintptr(unsafe.Pointer(&pPrnInfo))

上面代码中的两个地方都是错误的；它为您提供了一个指向切片头的指针，而不是指向实际支持数组的指针。你想要这个：

uintptr(unsafe.Pointer(&pPrnInfo[0]))

（由于支持数组是连续的，指向支持数组第一个元素的指针与指向支持数组本身的指针相同。）