This is a service routine to be provided as a " source" routine for the AST_CHANNEL function. It reads data from an HDS object (in response to reading from an AST_ Channel) and delivers it to the AST_ library for interpretation.

This routine has only a STATUS argument, so it communicates with other KPG routines via global variables stored in the KPG_AST common blocks. These are described below under " Global Variables used as Arguments" .

CALL KPG1_RDAST

STATUS = INTEGER (Given and Returned)

ASTLC = CHARACTER $\ast$ ( DAT__SZLOC ) (Given) A locator for the HDS object which holds the data. This must be a one-dimensional _CHAR array, whose size and character string length will be determined via this locator. ASTLN = INTEGER (Given and Returned) This must initially be set to the value 1, to indicate that data will be read starting at the first element of the HDS array (note the routine will not operate correctly unless 1 is the initial value - you cannot start reading at another point in the array if you have previously read from a different array). On exit it will be incremented by the number of elements used to obtain data, so that it identifies the first element to be used on the next invocation. ASTPT = INTEGER (Given) A pointer to the contents of the HDS object, mapped in ’ READ’ mode.