>How do I store or retrive information in fields that are marked with the flags "sys+bin", (0x01 + 0x04) as specified in vfp help:
>
>18 Field Flags::
>0x01 System Column (not visible to user)
>0x02Column can store null values
>0x04Binary column (for CHAR and MEMO only).
>
>If I try to display the contents with the sintax: ? table.field1 I receive the message "Variable 'xxxx' is not found".
>
>Thanks in advance.

Gustavo,
You'd need exclusive access :

*SetRemoveSysFlag
lparameters tcTableName, tnFieldNumber, tlSet
* tcTableName   : table to set-remove system flag
* tnFieldNumber : field number
* tlSet         : If .t. set otherwise (default) remove system flag
local handle, lnsecs
handle = this.OpenFile(fullpath(tcTableName)) && Openfile tries to open
if handle < 0
	return .f.
endif 
=fseek(handle,31+(tnFieldnumber-1)*32+18)
if tlSet
	=fwrite(handle,chr(bitor(val(fread(handle,1)),1)))
else
	=fwrite(handle,chr(bitand(val(fread(handle,1)),254)))
endif
=fclose(handle)

Cetin