The Scan for Characters and Return Relative Position routine is
    used to find a specified set of characters in the source string.
    LIB$SCANC makes the VAX SCANC instruction available as a callable
    routine.

    Format

      LIB$SCANC  source-string ,table-array ,byte-integer-mask

1  –  Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

    Relative position in the source string of the character that
    terminated the operation, or zero if the terminator character is
    not found. If the source string has a zero length, then a zero is
    returned.

2  –  Arguments

 source-string

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor

    Source string used by LIB$SCANC to index into a table. The
    source-string argument contains the address of a descriptor
    pointing to this source string.

 table-array

    OpenVMS usage:vector_mask_byte
    type:         byte (unsigned)
    access:       read only
    mechanism:    by reference, array reference

    Table that LIB$SCANC indexes into and performs a logical AND
    operation with the byte-integer-mask byte. The table-array
    argument contains the address of an unsigned byte array that
    is this table.

 byte-integer-mask

    OpenVMS usage:mask_byte
    type:         byte (unsigned)
    access:       read only
    mechanism:    by reference

    Mask on which a logical AND operation is performed with bytes in
    table-array. The byte-integer-mask argument contains the address
    of an unsigned byte that is this mask.