Re: [Libusb-win32-devel] Return values

[Stephan M. <ste...@we...>]

> Hi there,
> 
>  
> 
> Is there a table of the function's return values?

The error code are defined in errno.h. -5 means EIO (i/o error)

> 
>  
> 
> I'm using a test board that has four devices with the same characteristics, such as vendor and product 
> ids, number of and address of endpoints, and all others. But when I try to use more than two of these 
> devices, I get a -5 error from the function usb_set_configuration() on the third device (after accessing
> writing and reading from the other two).

This could be either a power or bandwidth problem. Windows will refuse to configure
the devices of they request too much power or bandwidth.

What's the bMaxPower value of your device's config descriptor? Are your four
devices connected to a bus-powered or to a self-powered hub?

Do your devices have interrupt or isochronous endpoints?

Stephan



> 
>  
> 
> Does anyone know what might be happening? Thanks in advance.
> 
>  
> 
> Dan Leite Martins
> 
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