comedi_arm — arm a subdevice
#include <comedilib.h>
| int comedi_arm( | comedi_t * device, | 
| unsigned int subdevice, | |
| unsigned int source ); | 
This function arms a subdevice.  It may, for example, arm a counter to
begin counting.  The source
parameter specifies what source should trigger the subdevice to begin.
The possible sources are driver-dependant.  This function is only
useable on subdevices that provide support for the
INSN_CONFIG_ARM configuration instruction.
Some subdevices treat this as an instruction to arm a specific channel.
For those subdevices, this function will arm channel
0 and comedi_arm_channel
should be called instead of this one to specify the channel.