Determines if there is another line of text to be displayed for this
      field. It treats the help_txt variable as a two dimensional array. When
      the array points to a zero value it indicates that we are at the end of
      the help text for this field. The first array dimension is indexed by
      the mfp_field variable which indicates what field number we are at any
      given point. The second dimension indexes which line of text is being
      referenced.

    Line 258:

      Displays the line of text pointed to by the two dimensional pointer,
      help_txt. The 'x' indexer is post incremented to point to the next line.

    Lines 255 - 258:

      Loop until a zero value is resolved. This zero is stored at the end of
      each field help string set.

                                      24


MFP RUN TIME ERROR MESSAGES

    MFP generates very few run time messages, mostly because of its
    structure. The error checking that MFP does perform is mostly limited
    to the mfp() function itself and primarily only to picture formatting
    and input field declaration. MFP will not generate field overflow or
    other like messages - it is only concerned about your definitions, which
    are hard-coded by you. Unless you write self-modifying code, you should
    not expect messages from MFP. If you do get messages from MFP and you
    know that your declarations are correct, be on the lookout for ill-
    behaved memory usage. For instance, when you clear an array's contents
    make sure you are remaining within its boundries, if you go beyond, you
    will be destroying possible string space or even worse, the program itself.

*ERROR* Picture Format Invalid ->  <your format here>

        This error is generated when mfp is extracting the variable type
        out of your picture string. No match was found for the nine data
        types that mfp supports. Mfp expects the following data types and
        cannot understand any others - also watch out for upper and lower
        case. Any picture format that begins with a "%" symbol is assumed
        by mfp() to be a numeric and will be type checked as one and must
        have the following type identifiers at the end of the picture
        string : "ld","hd","d","lu","u","Lf","lf","f". If your picture
        string begins without the "%" symbol, mfp() will assume that the
        entry is a character string or array.

*ERROR* Missing format length ->  <your format here>

        This error is generated when mfp is setting up the input field
        length. This error occurs only on numeric entry fields. If you
        neglected to pass a length modifier in your picture format, you
        can expect to see this error message. Numeric entry picture strings
        MUST have a length modifier so mfp() can build an entry field of
        that size for your user to input the data. The mfp() function makes
        no assumptions about field length for any numeric type. A properly
        declared picture for a five digit unsigned long integer would look
        like "%5lu". Mfp uses the '5' to build an entry field five characters
        in length.

*ERROR* Length too short ->  <your format here>

        This error occurs only on floating point numeric entry with a
        decimal point involved in the picture. When mfp() gets the field
        length and the number of digits to the right of the decimal point,
        it checks to see if you have given enough room in the field length
        for the sign, decimal point itself, and one digit to the left. This
        means that mfp() needs at least a field length of three digits more
        than the number of digits to the right of the decimal. For example
        if you wanted to define a field for the entry of a floating point
        number that had four decimal digits to the right of the decimal,
        the minimum field length would be seven digits, "%7.4f". If you
        were to define a field as, "%10.8lf", mfp() would give you this
        error message because it couldn't build the field in ten digits and
        work properly. The proper definition would be, "%11.8lf" or "%10.7lf".
        The above examples are only minimums, you may exceed the minimums as
        your application demands, ie; "%12.2lf","%10.2Lf","%4.0f","%5f"...

                                      25

===============================================================================

MENU

===============================================================================

Function        User menu function with HOT key support.

Syntax          int menu( MENU **menulist, PROC **proclist )

Prototype in    mfp.h

Remarks         Returns an integer value representing the menu option selected.
                The return value would be from zero to N - 1. If the user
                presses the escape key, a value of -1 is returned.

                The menu() function presents to the user your menu and the help
                text if provided. The user knows which menu option he is at
                by menu() highlighting the current option. The user navigates
                through the menu list via the standard cursor keys. The user
                may also select an option by pressing the appropriate key, 
                this immediatly selects the option with one keypress. The user
                may also press the escape key and menu() will return with a -1.
                When the user cursors over to the wanted selection, he must
                press enter to validate the selection and menu() returns with
                the integer value of his selection.

                The menu() function also supports HOT key PROC's. You must
                provide a PROC list, exactly as in mfp(). If the user presses
                a PROC key, the menu() function will execute the PROC and
                return back to the menu when completed.

                The menu() function requires a MENU list. This list is a
                group of menu items in the order of value you want returned.
                The first item of a menu list, if selected, will have a value
                of zero; the second item will have a value of one; and so-on
                for the rest. The MENU list MUST be terminated with a zero to
                identify the end of the list.

                The menu() function can accept a PROC list for HOT key PROC
                capability. If you don't wan't PROC key support you must
                pass a zero as the PROC parameter.

















                                      26

                                                                        menu

    MENU ITEM DEFINITION:

                Each menu item is defined using the typedef MENU. This
                simplifies your coding and makes defining a menu a snap.

                An example menu item is defined as follows:

                MENU item1[] = { 10, 20, "Edit", 'E', "Edit the above data." };

                The typedef MENU is followed by an item name which must be
                unique. The item must be declared as an array. The array is
                to be defined by direct assignment using the equals symbol
                followed by an open brace.

                The first parameters in the braces are the row and column
                respectively. This is the row and column where this item will
                appear on the screen.

                The next parameter is the item text that will be displayed.

                Following the item text is the alternate keyboard key that
                can also be used to select this item. If this key is pressed,
                this item will be selected and menu() will return with this
                menu item's value. This parameter MUST be uppercase, because
                the keyboard input will be converted to uppercase for testing.

                Last but not least, is the optional help text that will be
                displayed when this menu item is highlighted. If you do not
                want any help text to be displayed, you must place a zero in
                this parameter.

                Finally the menu declaration must be terminated with a close
                brace and a semicolon.

    THE MENU LIST:

                The menu list directs menu() to show the menu items in the
                order you established in the list, the return value starting
                from zero indicates the selection the user made, the first item
                in the menu list being zero and the last; N - 1. The menu list
                MUST be terminated with a zero. The menu list must be declared
                with the typedef MENU as an array of pointers.

                MENU *menulist[] = { item1, item2, item3, 0 };

    THE MENU COLOR:

                The menu function defaults to a white on black menu with
                the highlighted selection being black on white. This can
                be altered by changing the value of the following global
                variables that menu() uses:

                    MENNORMFG   This is the normal menu foreground attribute.
                    MENNORMBG   This is the normal menu background attribute.
                    MENLITEFG   This is the highlighted foreground attribute.
                    MENLITEBG   This is the highlighted background attribute.

                                      27

                                                                        menu
    THE HELP TEXT:

                The help text parameter is displayed when the user
                navigates to a menu item that has a help text line
                declared other than a zero. This text must not go beyond
                the 80th column. The help text line is cleared before
                the text is displayed so shorter lines won't appear with
                the remnents of a previous longer line.

                The help text is defaulted to be displayed on row 25
                column 1 with a WHITE on BLACK attribute with a maximum
                text length of 80 characters.

                The help text position and attributes can be changed by
                modifying the contents of the following global variables:

                    MENHLPROW   This is a global integer that is used for
                                the row position of the menu help text.

                    MENHLPCOL   This global integer is used for the column
                                position of the menu help text.

                    MENHLPLEN   This global integer is used to determine
                                the maximum length of the help text. This,
                                plus the MENHLPCOL, cannot extend past column
                                80 on the screen. MENHLPCOL + MENHLPLEN <= 80

                    MENHLPFG    This global integer is used for the foreground
                                attribute of the help text color.

                    MENHLPBG    This global integer is used for the background
                                attribute of the help text color.

                The above variables are declared in the mfp library and
                prototyped for you in mfp.h. To change one or more of the
                the above items you only need to assign the value with an
                assignment statement, ie;
                                            MENHLPROW = 2;

                This assignment changed the help text row to row 2. Any
                changes to these variables are global and remain until
                changed again.


    MENU INITIAL POSITIONING:

                The initial menu selection can be preset within the
                range of menu options present.

                MENSELPOS   --  This is the global menu initial position
                                variable. It is normally set to (-1), this
                                makes the menu start at the top item. Any
                                other value of 0 to n-1 will highlite the
                                appropriate selection.

                The menu function does not modify the value of MENSELPOS.
                MENSELPOS is a signed integer.

                                      28

                                                                        menu

EXAMPLE:


                #include <stdio.h>
                #include <mfp.h>

                MENU item1[] = { 10,20, "1) Accounts receivable.", '1', 0 };
                MENU item2[] = { 12,20, "2) Accounts payable....", '2', 0 };
                MENU item3[] = { 14,20, "3) Payroll.............", '3', 0 };
                MENU item4[] = { 16,20, "4) General ledger......", '4', 0 };
                MENU item5[] = { 20,20, "Exit...................", 'Q', 
                                        "Exit this program to DOS..." };

                MENU *mainmenu[] =  {
                                        item1, item2, item3, item4, item5, 0
                                    };


                void main( void )
                {
                    int menu_sel;

                    do
                    {
                        clrscr();

                        menu_sel = menu( mainmenu, 0 );

                        switch( menu_sel )
                        {
                            case 0:
                                    accrecv();
                                    break;
                            case 1:
                                    accpay();
                                    break;
                            case 2:
                                    payroll();
                                    break;
                            case 3:
                                    genldgr();
                                    break;
                            default:
                                    break;
                        }

                    } while( menu_sel != 4 && menu_sel != -1 );

                    return;
                }







                                      29

===============================================================================

PIC

===============================================================================

Function        Single line character entry with picture formatting.

Syntax          char *pic( char *data, char *picture )

Prototype in    mfp.h

Remarks         

                Pic() returns a pointer to the character string provided as
                the data parameter. It acts as a replacement for gets(),
                with all the line editing features of mfp(). A character
                picture string is required. Pic() terminates when the user
                presses the enter or escape key. Since the same keys are used
                for editing as in mfp(), pic is an ideal choice for single
                field entry.

                The escape key clears the input field and pic terminates.

                Pic() pads any trailing white space with