Open Page Setup Dialog box using Win API comdlg32.dll

Hello! :wave:
I'm a bit confused about your title - you mention both API and the comdlg32.dll.

You can open the Page Setup dialog box like:
commondialog1.cancelerror = true
commondialog1.flags = cdlPDPrintSetup
commondialog1.showprinter

API you could use
Public Declare Function OpenPrinter Lib "winspool.drv" _
Alias "OpenPrinterA" _
(ByVal pPrinterName As String, _
phPrinter As Long, _
pDefault As PRINTER_DEFAULTS) As Long

Public Declare Function SetPrinter Lib "winspool.drv" _
Alias "SetPrinterA" _
(ByVal hPrinter As Long, _
ByVal Level As Long, _
pPrinter As Any, _
ByVal Command As Long) As Long

Public Declare Function GetPrinter Lib "winspool.drv" _
Alias "GetPrinterA" _
(ByVal hPrinter As Long, _
ByVal Level As Long, _
pPrinter As Any, _
ByVal cbBuf As Long, _
pcbNeeded As Long) As Long

Public Declare Function ClosePrinter Lib "winspool.drv" _
(ByVal hPrinter As Long) As Long

' constants for DEVMODE structure
Public Const CCHDEVICENAME = 32
Public Const CCHFORMNAME = 32

' constants for DesiredAccess member of PRINTER_DEFAULTS
Public Const STANDARD_RIGHTS_REQUIRED = &HF0000
Public Const PRINTER_ACCESS_ADMINISTER = &H4
Public Const PRINTER_ACCESS_USE = &H8
Public Const PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED Or _
PRINTER_ACCESS_ADMINISTER Or PRINTER_ACCESS_USE)

' constant that goes into PRINTER_INFO_5 Attributes member
' to set it as default
Public Const PRINTER_ATTRIBUTE_DEFAULT = 4

Public Type DEVMODE
dmDeviceName As String * CCHDEVICENAME
dmSpecVersion As Integer
dmDriverVersion As Integer
dmSize As Integer
dmDriverExtra As Integer
dmFields As Long
dmOrientation As Integer
dmPaperSize As Integer
dmPaperLength As Integer
dmPaperWidth As Integer
dmScale As Integer
dmCopies As Integer
dmDefaultSource As Integer
dmPrintQuality As Integer
dmColor As Integer
dmDuplex As Integer
dmYResolution As Integer
dmTTOption As Integer
dmCollate As Integer
dmFormName As String * CCHFORMNAME
dmLogPixels As Integer
dmBitsPerPel As Long
dmPelsWidth As Long
dmPelsHeight As Long
dmDisplayFlags As Long
dmDisplayFrequency As Long
dmICMMethod As Long ' // Windows 95 only
dmICMIntent As Long ' // Windows 95 only
dmMediaType As Long ' // Windows 95 only
dmDitherType As Long ' // Windows 95 only
dmReserved1 As Long ' // Windows 95 only
dmReserved2 As Long ' // Windows 95 only
End Type

Public Type PRINTER_INFO_5
pPrinterName As String
pPortName As String
Attributes As Long
DeviceNotSelectedTimeout As Long
TransmissionRetryTimeout As Long
End Type

Public Type PRINTER_DEFAULTS
pDatatype As Long
pDevMode As Long
DesiredAccess As Long
End Type

To obtain your desired info.