pvDataCPP documentation

• This module is included in EPICS Base releases beginning with 7.0.1
• It may also be Downloaded and built separately.
• API components
• Release Notes

The epics::pvData namespace. See pv/pvData.h header.

#include <pv/pvData.h>
#include <pv/createRequest.h>

• Type description epics::pvData::Field and sub-classes
• Value container epics::pvData::PVField and sub-classes
• POD array handling epics::pvData::shared_vector
• pvRequest parsing epics::pvData::createRequest()

Define a structure type and create a container with default values.

namespace pvd = epics::pvData;
pvd::StructureConstPtr stype(pvd::FieldBuilder::begin()
                        ->add("fld1", pvd::pvInt)
                        ->addNestedStructure("sub")
                            ->add("fld2", pvd::pvString)
                        ->endNested()
                        ->createStructure());

pvd::PVStructuretPtr value(stype->build());

value->getSubFieldT<pvd::PVInt>("fld1")->put(4); // store integer 4.  would throw if not pvInt
value->getSubFieldT<pvd::PVScalar>("sub.fld2")->putFrom(4.2); // convert and store string "4.2"

is equivalent to the following pseudo-code.

struct stype {
    pvd::int32 fld1;
    struct {
        std::string fld2;
    } sub;
};
stype value;
value.fld1 = 4;
value.fld2 = pvd::castUnsafe<std::string>(4.2);