(SYSLIB) Programming Reference Manual - Public Support Login ...

packet
INFOR$–Internal Format Table Interface Routines
Address of the 30-word packet required by the common bank version of INFOR$
routine. This parameter is ignored unless parameter t is set to 'A' or 'CB'. If the
common bank version of the SINF$ routine is being called and this parameter is
omitted, then the routine assumes the address has already been loaded into register
A2 by the calling program.
Returns
There is a special case where an element name is preceded by a period and entered
without a filename.
@processor .element
This is normally interpreted to mean that the file name for the present subfield is either
TPF$ (if it is the first subfield) or it is the same file name as in the previous subfield.
When SINF$ is used to retrieve the element name and this condition exists, SINF$
makes a normal find-return to the calling program with the element name in the register
pair A0,A1 and sets the FCI field in the subfield control word to an octal 75. (Octal 75 is
the Fieldata code for a period.) Register A2 contains the address of the subfield control
word and the following test can be used to detect this condition.
TNZ,S4 0,A2
The instruction immediately after the TNZ will be skipped if the element name was given
on the processor call line with a leading period but no file name.
Another special case is when there is no qualifier in a field but an asterisk precedes the
file name.
@processor *file.
In this case, if SINF$ is used to retrieve the qualifier, it makes a normal find-return to the
calling program with blanks in the register pair A0,A1. When the processor call line
specifies a file name with no qualifier or leading asterisk
@processor file.
SINF$ takes the no-find-return if asked to retrieve the qualifier.
When a find-return occurs, the registers contain:
A0,A1 the contents of the specified subfield in Fieldata (left-justified, space-filled).
A2 (H2) location of subfield control word (see Appendix G).
A3 number of characters.
When a no-find-return occurs, A2 points to the word that stopped the search. If this
word is zero, the end of the INFOR table has been reached.
7833 1733–004 12–7