We try to find the smallest diff by comparing each diff with
the previously known smallest diff, so initially, this smallest diff
should be INFINITY so that we are sure to find a smaller one.
This fixes the following exception:
sr: rigol-ds: Negative vdiv index: -1.
Caught exception: not applicable
These are available on e.g. Rigol DS1102E (or "upgraded" DS1052E).
Without this, if one of the channels happens to have been set to
one of the missing vdiv settings frontends (e.g. PulseView) will
have some trouble using the scope:
sr: hwdriver: sr_config_get(): key 30012 (vdiv) sdi 0x11bcb70 cg CH1
sr: rigol-ds: Negative vdiv index: -1.
std::exception
Every driver now publishes its device option config keys, i.e. the
list fetched with sr_config_list(SR_CONF_DEVICE_OPTIONS), with a
set of flags indicating which methods are implemented by the driver
for that key.
The config keys are OR'ed with any combination of SR_CONF_GET,
SR_CONF_SET and SR_CONF_LIST. These are defined as the high bits
of the uint32_t config key. Clients can OR config keys with
SR_CONF_MASK to strip out these bits. This mask will be kept up to
date if other bits are added to the capabilities list; clients MUST
therefore use SR_CONF_MASK for this.
Some keys don't have capability bits added, such as the informative
device type keys (SR_CONF_MULTIMETER, SR_CONF_OSCILLOSCOPE, ...) and
SR_CONF_CONTINUOUS.
Scan options do not have capabilities bits.
Martin Ling
Aurelien Jacobs
Uwe Hermann
Soeren Apel
Bert Vermeulen