String PV

Hello,

I am writing a custom Background Program in C language to perform fast gathers.

One specification is that the user could be able to set the output file name on the GUI. By this reason, I would like to know if there is something related to read and write strings on PowerPMAC.

I saw this snippet of code on `pmacVariableWrite` [template](https://github.com/dls-controls/pmac/blob/dls-master/pmacApp/Db/pmacVariableWrite.template):

```python
record(ao, "$(P)$(Q):SET") {
field(DESC, "Write value to pmac")
field(DTYP, "$(DTYP=asynFloat64)")
field(SDIS, "$(P)$(Q):SYNC.PACT")
field(OUT, "@asyn($(PORT),0)PMAC_W$(TYPE=D)_$(VAR)")
}
```

and maybe this `TYPE` is the solution for my problem. I don`t know how to use it on both sides: EPICS and PowerPMAC; and I would like some help on it.

I also would like to know if I could just adapt `TYPE` of the same template on tag [2-4-11](https://github.com/dls-controls/pmac/tree/2-4-11) which is the running version on our entire lab. The following snippet of the same template for the variable write template of version 2-4-11 (Note that `TYPE` does not exist)

```python
record(ao, "$(P)$(Q):SET") {
field(DESC, "Write value to pmac")
field(DTYP, "asynFloat64")
field(SDIS, "$(P)$(Q):SYNC.PACT")
field(OUT, "@asyn($(PORT),0)PMAC_VDM_$(VAR)")
```

The Cdata shared memory was designed for string manipulation, could I have access to it from `pmacVariableWrite`?

Thanks in advance
George