sqlda value is NULL?

I am using sqlda EXEC SQL describe usqlobj into udesc; EXEC SQL declare usqlcurs cursor for usqlobj; EXEC SQL open usqlcurs; ... for(col=udesc->sqlvar,i=0;i<udesc->sqld;col++,i++) { switch(col->sqltype) { case SQLSMFLOAT: col->sqltype = CFLOATTYPE; col->sqldata = malloc(sizeof(float)); ... for each type } } EXEC SQL fetch usqlcurs using descriptor udesc; retcode = 0; ... for(col=udesc->sqlvar,i=0;i<udesc->sqld;col++,i++) { switch(col->sqltype) { case CFLOATTYPE: vWlog(LOGDB,"dblib2:dbSeqSelect: cfloat"); ifloat=(float) *((float *) (col->sqldata)); ... ... ... But if the data is null, how can I tell? Can I test on a variable? I have trying testing col->sqldata for null and looked at sqlidat and sqlind. Any suggestions? Thanks in advance. +------------------------------------+------------------------------------+ | Dana P. Hammond | E-mail: D.P.Hammond@LaRC.NASA.GOV | | CSC/NASA Langley Research Center | Fax: (804) 766-2571 | | Hampton, Virginia 23681-0001 | Mail Stop: 931 | | Phone: (804) 865-1725 | home: dana@infi.net | +------------------------------------+------------------------------------+