Amiga® RKM Libraries: 37 Utility Library

Utility library is the home for all the OS functions which don't fit in
the other libraries.  Among the calls in utility library are calls to
manage tags and tag lists, callback hooks, and some generic 32-bit math
functions, all discussed below.

 Tags                             International String Functions 
 Callback Hooks                   Date Functions 
 32-bit Integer Math Functions    Function Reference 


37 Utility Library / Tags

The implementation of tags is one of the many new features of Release 2.
Tags make it possible to add new parameters to system functions without
interfering with the original parameters.  They also make specifying
parameter lists much clearer and easier.

 Tag Functions and Structures    Simple Tag Usage Example 
 Simple Tag Usage                Advanced Tag Usage 


37 / Tags / Tag Functions and Structures

A tag is made up of an attribute/value pair as defined below (from
<utility/tagitem.h>):

    struct TagItem
    {
        ULONG  ti_Tag;    /* identifies the type of this item */
        ULONG  ti_Data;   /* type-specific data, can be a pointer */
    };

The ti_Tag field specifies an attribute to set.  The possible values of
ti_Tag are implementation specific.  System tags are defined in the
include files.  The value the attribute is set to is specified in ti_Data.
An example of the attribute/value pair that will specify a window's name
is:

    ti_Tag  = WA_Title;
    ti_Data = "My Window's Name";

The ti_Data field often contains 32-bit data as well as pointers.

These are brief descriptions of the utility functions you can use to
manipulate and access tags.  For complete descriptions, see the
"Simple Tag Usage" and "Advanced Tag Usage" sections.

The following utility library calls are for supporting tags:


                Table 37-1: Utility Library Tag Functions
  ______________________________________________________________________
 |                                                                      |
 |     AllocateTagItems()  Allocate a TagItem array (or chain).         |
 |         FreeTagItems()  Frees allocated TagItem lists.               |
 |----------------------------------------------------------------------|
 |        CloneTagItems()  Copies a TagItem list.                       |
 | RefreshTagItemClones()  Rejuvenates a clone from the original.       |
 |----------------------------------------------------------------------|
 |          FindTagItem()  Scans TagItem list for a tag.                |
 |           GetTagData()  Obtain data corresponding to tag.            |
 |          NextTagItem()  Iterate TagItem lists.                       |
 |           TagInArray()  Check if a tag value appears in a Tag array. |
 |----------------------------------------------------------------------|
 |     FilterTagChanges()  Eliminate TagItems which specify no change.  |
 |       FilterTagItems()  Remove selected items from a TagItem list.   |
 |              MapTags()  Convert ti_Tag values in a list via map      |
 |                         pairing.                                     |
 |         PackBoolTags()  Builds a "Flag" word from a TagItem list.    |
 |______________________________________________________________________|


37 / Tags / Simple Tag Usage

One way tags are passed to system functions is in the form of tag lists. A
tag list is an array or chain of arrays of TagItem structures.  Within
this array, different data items are identified by the value of ti_Tag.
Items specific to a subsystem (Intuition, Graphics,...) have a ti_Tag
value which has the TAG_USER bit set. Global system tags have a ti_Tag
value with TAG_USER bit clear.  The global system tags include:


                      Table 37-2: Global System Tags
  ____________________________________________________________________
 |                                                                    |
 | Tag Value   Meaning                                                |
 |====================================================================|
 | TAG_IGNORE  A no-op.  The data item is ignored.                    |
 |                                                                    |
 | TAG_MORE    The ti_Data points to another tag list, to support     |
 |             chaining of TagItem arrays.                            |
 |                                                                    |
 | TAG_DONE    Terminates the TagItem array (or chain).               |
 |                                                                    |
 | TAG_SKIP    Ignore the current tag item, and skip the next n array |
 |             elements, where n is kept in ti_Data.                  |
 |____________________________________________________________________|


Note that user tags need only be unique within the particular context of
their use.  For example, the attribute tags defined for OpenWindow() have
the same numeric value as some tags used by OpenScreen(), but the same
numeric value has different meaning in the different contexts.

System functions receive TagItems in several ways.  One way is illustrated
in the Intuition function OpenWindow().  This function supports an
extented NewWindow structure called ExtNewWindow.  When the NW_EXTENDED
flag is set in the ExtNewWindow.Flags field, OpenWindow() assumes that the
ExtNewWindow.Extension field contains a pointer to a tag list.

Another method of passing a tag list is to directly pass a pointer to a
tag list, as OpenWindowTagList() does in the following code fragment.

    struct TagItem tagitem[3];
    struct Screen *screen;
    struct Window *window;

    tagitem[0].ti_Tag = WA_CustomScreen;
    tagitem[0].ti_Data = screen;    /* Open on my own screen */
    tagitem[1].ti_Tag = WA_Title;
    tagitem[1].ti_Data = "RKM Test Window";
    tagitem[2].ti_Tag = TAG_DONE;   /* Marks the end of the tag array. */

    /* Use defaults for everything else. Will open as big as the screen. */
    /* Because all window parameters are specified using tags, we don't  */
    /* need a NewWindow structure                                        */

    if (window = OpenWindowTagList(NULL, tagitem))
    {
        /* rest of code */
        CloseWindow(window);
    }

Notice that window parameters need not be explicitly specified. Functions
that utilize tags have reasonable defaults to fall back on in case no
valid attribute/value pair was supplied for a particular parameter. This
fall back capability is a useful feature. An application only has to
specify the attributes that differ from the default, rather than
unnecessarily listing all the possible attributes.

The amiga.lib support library offers another way to pass TagItems to a
function.  Rather than passing a tag list, the function OpenWindowTags()
receives the attribute/value pairs in the argument list, much like
printf() receives its arguments.  Any number of attribute/value pairs can
be specified.  This type of argument passing is called VarArgs. The
following code fragment illustrates the usage of OpenWindowTags().

    struct Window *window;

    /* Just pass NULL to show we aren't using a NewWindow */
    window = OpenWindowTags( NULL,
                             WA_CustomScreen, screen,
                             WA_Title, "RKM Test Window",
                             TAG_DONE );

Tags are not exclusively for use with the operating system; the programmer
can implement them as well.  The run-time utility library contains several
functions to make using tags easier.


37 / Tags / Advanced Tag Usage

The previous section provided the background material necessary to start
using tags.  This section will show how to use the more advanced features
of tags using functions within utility library.

 Creating a New Tag List           Sequential Access of Tag Lists 
 Copying an Existing Tag List      Random Access of Tag Lists 
 Filtering an Existing Tag List    Obtaining Boolean Values 
 Locating an Attribute             Mapping Tag Attributes 


37 / / Advanced Tag Usage / Creating a New Tag List

The AllocateTagItems() function can be used to create a new tag array
ready for use.  The tag array should be passed to FreeTagItems() when the
application is done with it.

    struct TagItem *tags;
    ULONG tags_needed;

    /* Indicate how many tags we need */
    tags_needed = 10;

    /* Allocate a tag array */
    if (tags = AllocateTagItems(tags_needed))
    {
        /* ...do something with the array... */

        /* Free the array when your done with it */
        FreeTagItems (tags);
    }


37 / / Advanced Tag Usage / Copying an Existing Tag List

The CloneTagItems() function is used to copy an existing tag array into a
new tag array.

    struct TagItem *otags;      /* Original tag array */
    struct TagItem *ntags;      /* New tag array */

    /* Make sure there is a TagItem array */
    if (otags)
    {
        /* Copy the original tags into a new tag array */
        if (ntags = CloneTagItems(otags))
        {
            /* ...do something with the array... */

            /* Free the array when your done with it */
            FreeTagItems (ntags);
        }
    }

This function can also be used to implement a function that will insert
tag items into an array.

    struct TagItem *otags;      /* Original tag array */
    struct TagItem *tags;       /* New tag array */

    /* Insert a couple of tags into an existing tag array */
    if (tags = MakeNewTagList (GA_LeftEdge, 10,
                               GA_TopEdge, 20,
                               TAG_MORE, otags))
    {
        /* ...do something with the array... */

        /* Free the array when your done with it */
        FreeTagItems (tags);
    }

    /* This function will create a tag array from tag pairs placed on
     * the stack */
    struct TagItem *MakeNewTagList (ULONG data,...)
    {
        struct TagItem *tags = (struct TagItem *) &data;

        return (CloneTagItems (tags));
    }


37 / / Advanced Tag Usage / Filtering an Existing Tag List

Sometimes it is necessary to only allow certain attributes to be visible
in a tag list.  In order to achieve this, the tag array would need to be
filtered.

A number of functions are provided for filtering items in a tag array.
They are FilterTagChanges(), FilterTagItems() and RefreshTagItemClones().


    /* We want the text entry gadget to receive the following tags */
    Tag string_attrs[] =
    {
        STRINGA_MaxChars,
        STRINGA_Buffer,
        STRINGA_TextVal,
        TAG_END,
    };

    /* These are attributes that the model understands */
    Tag model_attrs[] =
    {
        CGTA_Total,
        CGTA_Visible,
        CGTA_Top,
        ICA_TARGET,
        ICA_MAP,
        TAG_END,
    };

    struct TagItem *otags;      /* Original tag list */
    struct TagItem *ntags;      /* New, work, tag list */

    /* Make a copy of the original for us to work with */
    ntags = CloneTagItems (otags);

    /* Create a tag list that only contains attributes that are
     * listed in the model_attrs list. */
    if (FilterTagItems (ntags, model_attrs, TAGFILTER_AND))
    {
        /* Work with filtered tag list (ntags) */

        /* Restore the tag list */
        RefreshTagItemClones (ntags, otags);

        /* Create a tag list that only contains attributes that
         * aren't in the model_attrs list. */
        if (FilterTagItems (ntags, model_attrs, TAGFILTER_NOT))
        {
            /* Work with filtered tag list (ntags) */
        }

        /* Restore the tag list */
        RefreshTagItemClones (ntags, otags);

        /* Create a tag list that only contains attributes that
         * are in the string_attrs list. */
        if (FilterTagItems (ntags, string_attrs, TAGFILTER_AND))
        {
            /* Work with filtered tag list (ntags) */
        }
    }

    /* Free work tag list. */
    FreeTagItems (ntags);


37 / / Advanced Tag Usage / Locating an Attribute

To see if an attribute is in a tag array, the TagInArray() function is
used.

    /* See if the listview labels attribute is located in a tag array */
    if (TagItemArray(GTLV_Labels, tags))
    {
        /* Yes, the attribute is in the list */
    }
    else
    {
        /* No, the attribute isn't in the list */
    }

The FindTagItem() function will return a pointer to the actual tag that
has the desired attribute.  This allows you to manipulate the tag or to
determine if the attribute exists but just has a NULL value.

    struct TagItem *tag;

    /* See if they are trying to set a sound */
    if (tag = FindTagItem(MGA_Sound, attrs))
    {
        /* Set the sound attribute to point to the specified sound data */
        tag->ti_Data = sound;
    }


37 / / Advanced Tag Usage / Sequential Access of Tag Lists

In order to sequentially access the members of a tag array, the
NextTagItem() function is used.

    struct TagItem *tags = msg->ops_AttrList;
    struct TagItem *tstate;
    struct TagItem *tag;
    ULONG tidata;

    /* Start at the beginning */
    tstate = tags;

    /* Step through the tag list while there are still items in the
     * list */
    while (tag = NextTagItem (&tstate))
    {
        /* Cache the data for the current element */
        tidata = tag->ti_Data;

        /* Handle each attribute that we understand */
        switch (tag->ti_Tag)
        {
            /* Put a case statement here for each attribute that your
             * function understands */
            case PGA_Freedom:
                lod->lod_Flags |= tidata;
                break;

            case GTLV_Labels:
                lod->lod_List = (struct List *) tidata;
                break;

            /* We don't understand this attribute */
            default:
                break;
        }
    }


37 / / Advanced Tag Usage / Random Access of Tag Lists

The GetTagData() function will return the data for the specified
attribute.  If there isn't a tag that matches, then the default value is
returned.

    APTR sound;

    /* Get the sound data that our function will use. */
    sound = (APTR) GetTagData (MGA_Sound, (ULONG) DefaultSound, attrs);


37 / / Advanced Tag Usage / Obtaining Boolean Values

Often times data is best represented as simple boolean (TRUE or FALSE)
values.  The PackBoolTags() function provides an easy method for
converting a tag list to bit fields.

    /* These are the attributes that we understand, with the
     * corresponding flag value. */
    struct TagItem activation_bools[] =
    {
        /* Attribute            Flags */
        {GA_ENDGADGET,          ENDGADGET},
        {GA_IMMEDIATE,          GADGIMMEDIATE},
        {GA_RELVERIFY,          RELVERIFY},
        {GA_FOLLOWMOUSE,        FOLLOWMOUSE},
        {GA_RIGHTBORDER,        RIGHTBORDER},
        {GA_LEFTBORDER,         LEFTBORDER},
        {GA_TOPBORDER,          TOPBORDER},
        {GA_BOTTOMBORDER,       BOTTOMBORDER},
        {GA_TOGGLESELECT,       TOGGLESELECT},

        /* Terminate the array */
        {TAG_END}
    };

    /* Set the activation field, based on the attributes passed */
    g->Activation = PackBoolTags(g->Activation, tags, activation_bools);


37 / / Advanced Tag Usage / Mapping Tag Attributes

To translate all occurrences of an attribute to another attribute, the
MapTags() function is used.

For Release 2, the third parameter of this function is always TRUE (tags
remain in the array even if they can't be mapped).

    struct TagItem map_list[] =
    {
        /* Original     New */
        {MGA_LeftEdge,  GA_LeftEdge},
        {MGA_TopEdge,   GA_TopEdge},
        {MGA_Width,     GA_Width},
        {MGA_Height,    GA_Height},

        /* Terminate the array */
        {TAG_END},
    }

    /* Map the tags to the new attributes, keeping all attributes that
     * aren't included in the mapping array */
    MapTags(tags, map_list, TRUE);


37 Utility Library / Callback Hooks

The callback features of Release 2 provide a standard means for
applications to extend the functionality of libraries, devices, and
applications.  This standard makes it easy for the operating system to use
custom modules from different high level programming languages as part of
the operating system.  For example, the layers library, which takes care
of treating a display as a series of layered regions, allows an
application to attach a pattern function to a display layer.  Instead of
filling in the background of a layer with the background color, the layers
library calls the custom pattern function which fills in the layer display
with a custom background pattern.

 Callback Hook Structure and Function 


37 / Callback Hooks / Callback Hook Structure and Function

An application passes a custom function in the form of a callback Hook
(from <utility/hooks.h>):

    struct Hook
    {
        struct MinNode h_MinNode;
        ULONG (*h_Entry)();     /* stub function entry point */
        ULONG (*h_SubEntry)();  /* the custom function entry point */
        VOID *h_Data;           /* owner specific */
    };

h_MinNode
    This field is reserved for use by the module that will call the Hook.

h_Entry
    This is the address of the Hook stub.  When the OS calls a callback
    function, it puts parameters for the callback function in CPU
    registers A0, A1, and A2.  This makes it tough for higher level
    language programmers to use a callback function because most higher
    level languages don't have a way to manipulate CPU registers
    directly.  The solution is a stub function which first copies the
    parameters from the CPU registers to a place where a high level
    language function can get to them.   The stub function then calls the
    callback function.  Typically, the stub pushes the registers onto the
    stack in a specific order and the callback function pops them off the
    stack.

h_SubEntry
    This is the address of the actual callback function that the
    application has defined.  The stub calls this function.

h_Data
    This field is for the application to use.  It could point to a global
    storage structure that the callback function utilizes.

There is only one function defined in utility library that relates to
callback hooks:

    ULONG CallHookPkt(struct Hook *hook, VOID *object, VOID *paramPkt);

This function calls a standard callback Hook function.

 Simple Callback Hook Usage 


37 / / Hook Structure And Function / Simple Callback Hook Usage

A Hook function must accept the following three parameters in these
specific registers:


      A0 - Pointer to the Hook structure.
      A2 - Pointer to an object to manipulate. The object is
           context specific.
      A1 - Pointer to a message packet. This is also context
           specific.


For a callback function written in C, the parameters should appear in this
order:

    myCallbackFunction(Pointer to Hook (A0),
                       Pointer to Object (A2),
                       Pointer to message (A1));

This is because the standard C stub pushes the parameters onto the stack
in the following order: A1, A2, A0.  The following assembly language
routine is a callback stub for C:

    INCLUDE 'exec/types.i'
    INCLUDE 'utility/hooks.i'

    xdef        _hookEntry

    _hookEntry:
        move.l  a1,-(sp)                ; push message packet pointer
        move.l  a2,-(sp)                ; push object pointer
        move.l  a0,-(sp)                ; push hook pointer
        move.l  h_SubEntry(a0),a0       ; fetch actual Hook entry point ...
        jsr     (a0)                    ; and call it
        lea     12(sp),sp               ; fix stack
        rts

If your C compiler supports registerized parameters, your callback
functions can get the parameters directly from the CPU registers instead
of having to use a stub to push them on the stack.  The following C
language routine uses registerized parameters to put parameters in the
right registers.  This routine requires a C compiler that supports
registerized parameters.

    #include 
    #include 

    #define     ASM     __asm
    #define     REG(x)  register __ ## x

    /* This function converts register-parameter hook calling
     * convention into standard C conventions.  It requires a C
     * compiler that supports registerized parameters, such as
     * SAS/C 5.xx or greater.
     */
    ULONG ASM
    hookEntry(REG(a0) struct Hook *h, REG(a2) VOID *o, REG(a1) VOID *msg)
    {
        return ((*h->h_SubEntry)(h, o, msg));
    }

A callback function is executed on the context of the module that invoked
it.  This usually means that callback functions cannot call functions that
need to look at environment specific data.  For example, printf() needs to
look at the current process's input and output stream.  Entities like
Intuition have no input and output stream.  This also means that in order
for the function to access any of its global data, it needs to make sure
the CPU can find the function's data segment.  It does this by forcing the
function to load the offset for the program's data segment into CPU
register A4.  See your compiler documentation for details.

The following is a simple function that can be used in a callback hook.

    ULONG MyFunction (struct Hook *h, VOID *o, VOID *msg)
    {
        /* A SASC and Manx function that obtains access to the global
           data segment */
        geta4();

        /* Debugging function to send a string to the serial port */
        KPrintF("Inside MyFunction()\n");

        return (1);
    }

The next step is to initialize the Hook for use.  This basically means
that the fields of the Hook structure must be filled with appropriate
values.

The following simple function initializes a Hook structure.

    /* This simple function is used to initialize a Hook */
    VOID InitHook (struct Hook *h, ULONG (*func)(), VOID *data)
    {
        /* Make sure a pointer was passed */
        if (h)
        {
            /* Fill in the hook fields */
            h->h_Entry = (ULONG (*)()) hookEntry;
            h->h_SubEntry = func;
            h->h_Data = data;
        }
    }

The following is a simple example of a callback hook function.

     hooks1.c 


37 Utility Library / 32-bit Integer Math Functions

Utility library contains some high-speed math functions for 32-bit integer
division and multiplication. These functions will take advantage of
available processor instructions (like DIVUL), if a 68020 processor or
higher is present. If not, these functions will mimic those instructions
in 68000 only instructions, thus providing processor independency.

Currently the following functions are implemented:

  ____________________________________________________________
 |                                                            |
 |  SDivMod32()  Signed 32 by 32-bit division and modulus.    |
 |    SMult32()  Signed 32 by 32-bit multiplication.          |
 |  UDivMod32()  Unsigned 32 by 32-bit division and modulus.  |
 |    UMult32()  Unsigned 32 by 32-bit multiplication.        |
 |____________________________________________________________|

       Table 37-3: Utility Library 32-bit Math Functions


The division functions return the quotient in D0 and the remainder in D1.
To obtain the remainder in a higher level language, either a compiler
specific instruction to fetch the contents of a specific register must be
used (like getreg() in SAS C) or a small assembler stub.

Following a simple example of the usage of the 32-bit integer math
functions in C.

     uptime.c 


37 Utility Library / International String Functions

The international string functions in utility library are a way to make
use of a future localization library which Commodore-Amiga will provide.
When the localization library is opened, the functions will be replaced by
ones which will take the locale as defined by the user into account. This
means that the compare order may change according to the locale, so care
should be taken not to rely on obtaining specific compare sequences.

Currently implemented are:

  _______________________________________________________________
 |                                                               |
 |  Stricmp()  Compare string case-insensitive.                  |
 | Strnicmp()  Compare string case-insensitive, with a specified |
 |             length.                                           |
 |  ToLower()  Convert a character to lower case.                |
 |  ToUpper()  Convert a character to upper case.                |
 |_______________________________________________________________|

    Table 37-4: Utility Library International String Functions


These functions operate in the same manner as their ANSI C equivalents,
for the most part.  For more information, see the "Utility Library"
Autodocs in the Amiga ROM Kernel Reference Manual: Includes and Autodocs.
Here is a simple example of the usage of the international string
functions.

     istr.c 


37 Utility Library / Date Functions

To ease date-related calculations, the utility library has some functions
to convert a date, specified in a ClockData structure, in the number of
seconds since 00:00:00 01-Jan-78 and vice versa. To indicate the date, the
ClockData structure (in <utility/date.h>) is used.

    struct ClockData
    {
        UWORD sec;     /* seconds (0 - 59)*/
        UWORD min;     /* minutes (0 - 59) */
        UWORD hour;    /* hour (0 - 23) */
        UWORD mday;    /* day of the month (1 - 31) */
        UWORD month;   /* month of the year (1 - 12)
        UWORD year;    /* 1978 - */
        UWORD wday;    /* day of the week (0 - 6, where 0 is Sunday) */
    };

The following functions are available to operate on ClockData:

  ________________________________________________________________
 |                                                                |
 | Amiga2Date()  Calculate the date from the specified timestamp  |
 |               (in seconds).                                    |
 |  CheckDate()  Check the legality of a date.                    |
 | Date2Amiga()  Calculate the timestamp from the specified date. |
 |________________________________________________________________|

            Table 37-5: Utility Library Date Functins


Amiga2Date() takes a number of seconds from 01-Jan-78 as argument and
fills in the supplied ClockData structure with the date and time.

CheckDate() checks if the supplied ClockData structure is valid, and
returns the number of seconds from 01-Jan-78 if it is. Note that this
function currently does not take the supplied day of the week in account.

Date2Amiga() takes a ClockData structure as argument and returns the
number of seconds since 01-Jan-78. The supplied ClockData structure MUST
be valid, since no checking is done.

The following example shows various uses of the utility library date
functions.

     a2d.c 


37 Utility Library / Function Reference

The tables which follow contain breif descriptions of the functions inside
the utility library.  All these functions require Release2 or a later
version of the Amiga operating system.  See the Amiga ROM Kernel Reference
Manual: Includes and Autodocs for details on each function call.

 Tag Function Reference 
 Callback Hook Function Reference 
 32-Bit Integer Math Function Reference 
 International String Function Reference 
 Date Function Reference 


37 / Function Reference / Tag Function Reference

The following are brief descriptions of the utility library functions
which pertain to tags and tag lusts.


                    Table 37-6: Utility Tag Functions
  ______________________________________________________________________
 |                                                                      |
 |           Function                 Description                       |
 |======================================================================|
 |     AllocateTagItems()  Allocate a TagItem array (or chain).         |
 |         FreeTagItems()  Frees allocated TagItem lists.               |
 |----------------------------------------------------------------------|
 |        CloneTagItems()  Copies a TagItem list.                       |
 | RefreshTagItemClones()  Rejuvenates a clone from the original.       |
 |----------------------------------------------------------------------|
 |          FindTagItem()  Scans TagItem list for a tag.                |
 |           GetTagData()  Obtain data corresponding to tag.            |
 |          NextTagItem()  Iterate TagItem lists.                       |
 |           TagInArray()  Check if a tag value appears in a Tag array. |
 |----------------------------------------------------------------------|
 |     FilterTagChanges()  Eliminate TagItems which specify no change.  |
 |       FilterTagItems()  Remove selected items from a TagItem list.   |
 |              MapTags()  Convert ti_Tag values in a list via map      |
 |----------------------------------------------------------------------|
 |         PackBoolTags()  Builds a "Flag" word from a TagItem list.    |
 |______________________________________________________________________|


37 / Function Reference / Callback Hook Function Reference

The following are brief descriptions of the utility library functions
which pertain to callback hooks.


                   Table 37-7: Utility Hook Functions
     ___________________________________________________________
    |                                                           |
    |    Function                 Description                   |
    |===========================================================|
    |  CallHookPkt()  Call a standard callback Hook function.   |
    |___________________________________________________________|


37 / Function Reference / 32-Bit Integer Math Function Reference

The following are brief descriptions of the utility library functions
which pertain to 32-bit integer math.


              Table 37-8: Utility 32-Bit Math Functions
     ___________________________________________________________
    |                                                           |
    |   Function                 Description                    |
    |===========================================================|
    |  SDivMod32()  Signed 32 by 32-bit division and modulus.   |
    |    SMult32()  Signed 32 by 32-bit multiplication.         |
    |-----------------------------------------------------------|
    |  UDivMod32()  Unsigned 32 by 32-bit division modulus.     |
    |    UMult32()  Unsigned 32 by 32-bit multiplication.       |
    |___________________________________________________________|


37 / Function Reference / International String Function Reference

The following are brief descriptions of the utility library functions
which pertain to string operations using the international ASCII character
set.

          Table 37-9: Utility International String Functions
   _________________________________________________________________
  |                                                                 |
  |   Function               Description                            |
  |=================================================================|
  |   Stricmp()  Compare strings, case-insensitive.                 |
  |  Strnicmp()  Compare strings, case-insensitive, with specified  |
  |              length.                                            |
  |-----------------------------------------------------------------|
  |   ToLower()  Convert a character to lower case.                 |
  |   ToUpper()  Convert a character to upper case.                 |
  |_________________________________________________________________|


37 / Function Reference / Date Function Reference

The following are brief descriptions of the utility library functions
which pertain to date conversion.


                   Table 37-10: Utility Date Functions
   ________________________________________________________________
  |                                                                |
  |    Function           Description                              |
  |================================================================|
  |   CheckDate()  Check the legality of a date.                   |
  |----------------------------------------------------------------|
  |  Amiga2Date()  Calculate the date from a specified timestamp.  |
  |  Date2Amiga()  Calculate the timestamp from a specified date.  |
  |________________________________________________________________|


Converted on 22 Apr 2000 with RexxDoesAmigaGuide2HTML 2.1 by Michael Ranner.