UsbQueryNumberDevices: Difference between revisions
Created page with "==Description== Obtains the total number of USB devices currently attached. ==Syntax== <pre> ulrc=UsbQueryNumberDevices(*pulNumDev) </pre> ==Parameters== ; pulNumDev : ==R..." |
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==Description== | ==Description== | ||
Obtains the total number of USB devices | Obtains the total number of currently attached USB devices. | ||
==Syntax== | ==Syntax== | ||
ulrc = UsbQueryNumberDevices(pulNumDev) | |||
ulrc=UsbQueryNumberDevices( | |||
==Parameters== | ==Parameters== | ||
; pulNumDev : | ; pulNumDev : the address of the variable to receive the Total Number. | ||
==Return Code== | ==Return Code== | ||
0x0000 - NO_ERROR | |||
===Errors=== | ===Errors=== | ||
<pre> | |||
0x0057 - ERROR_INVALID_PARAMETER | |||
0x1B58 - USB_NOT_INIT | |||
0xFF13 - ERROR_I24_INVALID_PARAMETER | |||
0xFF1F - ERROR_GEN_FAILURE | |||
0xFF57 - ERROR_INVALID_PARAMETER | |||
</pre> | |||
==Remarks== | ==Remarks== | ||
| Line 25: | Line 24: | ||
==Example Code== | ==Example Code== | ||
<pre> | <pre> | ||
//Code Snippet - UsbQueryNumberDevices | |||
{ | |||
APIRET ulrc; | |||
PULONG pulNumDev; | |||
ULONG ulNumDev; | |||
pulNumDev = &ulNumDev; | |||
ulrc = UsbQueryNumberDevices(pulNumDev); | |||
printf("\nUsbQueryNumberDevices - ulrc: 0x%04X (%hu)",ulrc,ulrc); | |||
if (!ulrc) //success | |||
{ | |||
printf(" - NumberDevices: %hu",ulNumDev); | |||
} | |||
} | |||
</pre> | </pre> | ||
==Related Functions== | ==Related Functions== | ||
* [[UsbQueryDeviceReport]] | |||
* [[UsbQueryDeviceInfo]] | |||
* [[UsbOpen]] | |||
[[Category:USBCalls]] | [[Category:USBCalls]] | ||
Latest revision as of 20:47, 13 September 2021
Description
Obtains the total number of currently attached USB devices.
Syntax
ulrc = UsbQueryNumberDevices(pulNumDev)
Parameters
- pulNumDev
- the address of the variable to receive the Total Number.
Return Code
0x0000 - NO_ERROR
Errors
0x0057 - ERROR_INVALID_PARAMETER 0x1B58 - USB_NOT_INIT 0xFF13 - ERROR_I24_INVALID_PARAMETER 0xFF1F - ERROR_GEN_FAILURE 0xFF57 - ERROR_INVALID_PARAMETER
Remarks
Example Code
//Code Snippet - UsbQueryNumberDevices
{
APIRET ulrc;
PULONG pulNumDev;
ULONG ulNumDev;
pulNumDev = &ulNumDev;
ulrc = UsbQueryNumberDevices(pulNumDev);
printf("\nUsbQueryNumberDevices - ulrc: 0x%04X (%hu)",ulrc,ulrc);
if (!ulrc) //success
{
printf(" - NumberDevices: %hu",ulNumDev);
}
}