The Skip Selected Characters routine is used to skip a specified
    set of characters in the source string. LIB$SPANC makes the VAX
    SPANC instruction available as a callable routine.

    Format

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

1  –  Returns

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

    The relative position in the source string of the character that
    terminated the operation is returned if such a character is
    found. Otherwise, zero is returned. 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$SPANC to index into table-array. 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$SPANC indexes into and performs an 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 that an 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.