Auto discovered network printers shows up twice (with cupsEnumDest())

[NilanjanaLodh]

I set up a pdf printer on a remote machine in the subnet(Simpulated through a virtual machine in bridged adapter mode) and shared it.
When I start my cups scheduler on the remote machine, the discovered printer shows up twice on the list.

I use cupsEnumDests(CUPS_DEST_FLAGS_NONE, -1, NULL, CUPS_PRINTER_LOCAL, CUPS_PRINTER_REMOTE, printDestName, NULL) to enumerate the printers.
Here printDestName is a callback function which prints the printer name to stdout.

All the other printers show up once; just each of the network printers show up twice.

[michaelrsweet]

What version of CUPS are you using? We recently fixed some bugs in this area in Github master...

[NilanjanaLodh]

I am using the lastest snapshot from this repo.
I did a git pull just before testing(today)

[michaelrsweet]

Hmm, can you attach the output of "lpstat -ev"?

[NilanjanaLodh]

Here is the output of lpstat -ev

Generic-CUPS-PDF-Printer
HP_LaserJet_M1120_MFP
Generic-CUPS-PDF-Printer
HP_LaserJet_M1120_MFP

[michaelrsweet]

OK, there was a bug in the lpstat program - it didn't parse the command-line arguments correctly so you are getting the -e output twice...

Please try again.

[NilanjanaLodh]

Here is the output of lpstat -ev

Generic-CUPS-PDF-Printer
HP_LaserJet_M1120_MFP
device for Generic-CUPS-PDF-Printer: cups-pdf:/
device for HP_LaserJet_M1120_MFP: usb://HP/LaserJet%20M1120%20MFP

---

These are manually configured printers.

The output of the program using cupsEnumDests() is:

Generic-CUPS-PDF-Printer
HP_LaserJet_M1120_MFP
PDFPrint @ nilanjana-lubuntuVM
PDFPrint @ nilanjana-lubuntuVM
Generic CUPS-PDF Printer @ nilanjana-lubuntuVM
Generic CUPS-PDF Printer @ nilanjana-lubuntuVM

[michaelrsweet]

OK, so you need to suppress duplicate destinations yourself in your application - I will make sure this is documented clearly.

Basically, cupsEnumDests is providing you with updates to existing queues as we get responses from Avahi (on Linux) or mDNSResponder (on macOS). See the sample code in the new CUPS Programming Manual (available on the CUPS web site under the "help" tab) for an example that uses cupsEnumDests to assemble an array of CUPS destinations (like cupsGetDests does, just under your code's control...)

[JonathanKang]

Sorry to bump this thread.

I'm using cupsGetDests to get a list of destinations. Do I need to manually suppress duplicate destinations as well?

Thanks in advance.