The Disable CLI Interception of Control Characters routine
    requests the calling process's command language interpreter (CLI)
    to not intercept the selected control characters when they are
    entered during an interactive terminal session. LIB$DISABLE_CTRL
    provides the same function as the DCL command SET NOCONTROL.

    Format

      LIB$DISABLE_CTRL  disable-mask [,old-mask]

1  –  Returns

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

2  –  Arguments

 disable-mask

    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference

    Bit mask indicating which control characters are not to be
    intercepted. The disable-mask argument is the address of an
    unsigned longword containing this bit mask.

    Each of the 32 bits corresponds to one of the 32 possible control
    characters. If a bit is set, the corresponding control character
    is no longer intercepted by the CLI. Currently, only bits 20 and
    25, corresponding to Ctrl/T and Ctrl/Y, are recognized.

    The following mask is defined in symbol libraries supplied by VSI
    to specify the value of disable-mask:

    Symbol          Hex Value     Function

    LIB$M_CLI_      %X'00100000'  Disables Ctrl/T
    CTRLT
    LIB$M_CLI_      %X'02000000'  Disables Ctrl/Y
    CTRLY

    If a set bit does not correspond to a character that the CLI can
    intercept, LIB$DISABLE_CTRL returns an error.

 old-mask

    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       write only
    mechanism:    by reference

    Previous bit mask. The old-mask argument is the address of an
    unsigned longword into which LIB$DISABLE_CTRL writes the old bit
    mask. The old bit mask is of the same form as disable-mask and
    indicates those control characters that were previously enabled.
    It may therefore be given to LIB$ENABLE_CTRL to reinstate the
    previous condition.