Freegroup

This instruction frees the memory of an instance and all the instances sharing the same allocation group.

Syntax

FreeGroup INSTANCE_VAR

See [allocgrp](../4gl/allocgrp.md) and [NewInstance](../4gl/newinstance.md) for more information on instance allocation and allocation groups.

Example

# Declare two instances
Local Instance MY_CUSTOMER Using C_CUSTOMER
Local Instance MY_SALESREP Using C_SALESREP
Local Instance MY_COUNTRY Using C_COUNTRY
# Allocate both instances in the same allocation group
  MY_CUSTOMER = NewInstance C_CUSTOMER AllocGroup Null
  MY_SALESREP = NewInstance C_SALESREP AllocGroup MY_CUSTOMER
  MY_SALESREP = NewInstance C_SALESREP AllocGroup MY_CUSTOMER
  MY_COUNTRY = NewInstance C_COUNTRY AllocGroup MY_SALESREP
 ...
# Free only the country instance
  FreeInstance MY_COUNTRY : # MY_CUSTOMER and MY_SALESREP still allocated
# Free the allocation group (this would have freed MYCOUNTRY also if it had not already been done)
  FreeGroup MY_CUSTOMER : # FreeGroup MY_SALESREP would have the same effect

Comment

`FreeGroup` frees the memory but does not change the pointers that refer to the resources. Using them after a `FreeGroup` will generate errors. It can be useful to reassign them to a `null` pointer.

Local Instance MY_CUSTOMER Using C_CUSTOMER
MY_CUSTOMER=NewInstance C_CUSTOMER AllocGroup Null
...
FreeGroup MY_CUSTOMER
MY_CUSTOMER=null

See also

Structure, Instance, SetInstance, NewInstance, null, allocgrp, cast, FreeInstance.