UsbQueryNumberDevices: Difference between revisions
m sections with no content |
added parameter descriptions and example code |
||
| Line 1: | Line 1: | ||
Obtains the total number of USB devices | ==Description== | ||
Obtains the total number of currently attached USB devices. | |||
==Syntax== | ==Syntax== | ||
<pre> | <pre> | ||
ulrc=UsbQueryNumberDevices( | ulrc = UsbQueryNumberDevices(pulNumDev) | ||
</pre> | </pre> | ||
==Parameters== | ==Parameters== | ||
; pulNumDev : | ; pulNumDev : the address of the variable to receive the Total Number. | ||
==Return Code== | ==Return Code== | ||
<pre> | |||
0x0000 - NO_ERROR | |||
</pre> | |||
===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== | |||
==Example Code== | |||
<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> | |||
==Related Functions== | |||
[[Category: | [[Category:USBCalls]] | ||
Revision as of 16:47, 26 January 2017
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);
}
}