NAME

DoCallback − Create a callback object

SYNOPSIS

C:

DtObject DoCallback(function,dataobject)
DtPtr function;
DtObject dataobject;

Fortran:

INTEGER∗4 DOCB(FUNCT,DATOBJ)
EXTERNAL INTEGER∗4 FUNCT
INTEGER∗4 DATOBJ

DESCRIPTION

DoCallback creates a callback object.  The function parameter is a pointer to a user-defined function.  The dataobject parameter is the handle of an object containing the associated run-time data for the user-defined function.  This parameter is created with either DoDataPtr <DODP> or DoDataVal <DODV>.  DoCallback calls function with the run-time data of dataobject. 

The format for the user-defined function in C is:

 user_fcn(data)
DtPtr data;           /∗ if DoDataPtr was used ∗/
Dt32bits data;        /∗ if DoDataVal was used ∗/

The format for the user-defined function in Fortran is:

 FCN(DATA)
INTEGER∗4 DATA
 

ERRORS

DoCallback will fail if dataobject is not a DataVal, DataPtr or DcNullObject <DCNULL>. 

[WARNING - invalid dataobject handle]

SEE ALSO

DdInqPickCallback(3D), DdSetPickCallback(3D), DoDataPtr(3D), DoDataVal(3D), DsExecuteObj(3D), DsExecutionAbort(3D), DsExecutionReturn(3D)

September 29, 2021