# Bind the Dynstruct to a Variable

> [HTML Version](bindthedynstruct.htm)

_Updated March 2025_

The binding operation associates a dynamic structure definition with a DYNSTRUCT variable, accomplished via one of the following methods.

map1 ds, DYNSTRUCT            \! sample dynamic struct  (used below)

map1 stvar, ST\_SOME\_STRUCT    \! sample defstruct          "   "

map1 bar, ST\_ANOTHER\_STRUCT   \! another sample defstruct  "   "



•	Explicit binding via [MX\_DYNSTRUCT](mx_dynstruct.htm.md):

xcall MIAMEX, MX\_DYNSTRUCT, DYNOP\_BIND, status, dsname\$, ds

•	Explicit binding via .[BINDSTRUCT](bindstruct.htm.md):

.BINDSTRUCT ds, stvar

•	Implicit DYNSTRUCT by passing an instance of a defined structure to a function which receives it as a DYNSTRUCT:

call Fn'Dive(ds=bar)   \! ST\_ANOTHER\_STRUCT will be embedded (because of how Fn'Dive receives it))

...

function Fn'Dive(ds as DYNSTRUCT)



Implicit binding works even for parameters defined with the :OUTPUTONLY qualifier. The received DYNSTRUCT variable will be empty regardless of the default value, if any, but will be bound. For example:

defstruct st\_cust

    map2 id,b,4

    map2 name,s,30

endstruct



map1 cust, st\_cust     

cust.id = 99

cust.name = "Jacob"



call fn'foo(ds=cust)

? cust.name                  \! will be "Finkleheimer"

end



function fn'foo(ds="" as dynstruct:outputonly)

    ? ds.name                \! will be "" because of :outputonly

    ds.name = "Finkleheimer" \! valid because ds auto-bound to st\_cust

    xputarg @ds              

endfunction



**See Also**

•	[Structure Definition Embedding](structuredefinitionembedding.htm.md)

**History**

2025 March, A-Shell 7.0.1770.0, compiler edit 1064:  The :OUTPUTONLY qualifier no longer disables implicit binding. Prior to this update, the references to ds.name inside the function would have generated error 70 (invalid dynstruct reference) because the :outputonly would have defeated the automatic binding.