Programming Languages Suite/ProgramD2.iso/T U R B O Language/Turbo Pascal V7.0/ONLINE.ZIP/UTILS.DOC

Text File | 1992-10-30 | 47KB | 1,288 lines

=======================================================================
                       Turbo Pascal Utilities
=======================================================================

-----------------------------------------------------------------------
                         Table of Contents
-----------------------------------------------------------------------
 1. The TOUCH utility
 2. The GREP utility
     The GREP switches
     How to search using GREP
     Examples using GREP
 3. The BINOBJ utility
 4. Using TPUMOVER, the unit mover
     A review of unit files
     Using TPUMOVER
 5. The Stand-Alone MAKE Utility
     Creating makefiles
      Comments
      Explicit rules
      Implicit rules
      Command lists
      Macros
       Defined test macro ($d)
       Base file name macro ($*)
       Full file name macro ($<)
       File name path macro ($:)
       File name and extension macro ($.)
       File name only macro ($&)
      Directives
     Using MAKE
      The BUILTINS.MAK file
      How MAKE searches for files
      MAKE command-line options
      MAKE error messages
       Fatal errors
       Errors
-----------------------------------------------------------------------

This file describes three stand-alone utility programs that come
with Turbo Pascal: TOUCH, GREP, BINOBJ, TPUMOVER and MAKE.

======================
 1. The TOUCH Utility
======================

There are times when you want to force a particular target file
to be recompiled or rebuilt, even though no changes have been
made to its sources. One way to do this is to use the TOUCH
utility included with Turbo Pascal. TOUCH changes the date and
time of one or more files to the current date and time, making it
"newer" than the files that depend on it.

To force a target file to be rebuilt, "touch" one of the files
that target depends on. To touch a file (or files), enter

   touch filename [ filename ... ]

at the DOS prompt. TOUCH will then update the file's creation
date(s).

Once you do this, you can invoke MAKE to rebuild the touched
target file(s).


=====================
 2. The GREP Utility
=====================

GREP is a powerful search utility that can look for text in
several files at once.

The command-line syntax for GREP follows:

   GREP [options] searchstring [filespec ... ]

where options consists of one or more single characters preceded
by a hyphen, searchstring defines the pattern to search for, and
filespec is the file specification. filespec tells GREP which
files (or groups of files) to search; it can be an explicit file
name or a generic file name incorporating the DOS wildcards (?
and *). You can also enter a path as part of filespec; if you use
filespec without a path, GREP only searches the current
directory. If you don't specify filespec, input to GREP must be
specified by redirecting stdin or piping.


 The GREP Switches
===================

In the command line, options are one or more single characters
preceded by a hyphen (-). Each individual character is a switch
that you can turn on or off: type the plus symbol (+) after a
character to turn the option on, or type a hyphen (-) after the
character to turn the option off.

The default is on (the + is implied): for example, -R means the
same thing as -R+. You can list multiple options individually
like this: -I -D -L). Or you can combine them like this: -ILD or
-IL -D, and so on). It's all the same to GREP.

Here is a list of the switches and their meanings:

   -C   Count only: Only a count of matching lines is printed.
        For each file that contains at least one matching line,
        GREP prints the file name and a count of the number of
        matching lines. Matching lines are not printed.

   -D   Directories: For each filespec specified on the command
        line, GREP searches for all files that match the file
        specification, both in the directory specified and in all
        subdirectories below the specified directory. If you give
        a filespec without a path, GREP assumes the files are in
        the current directory.

   -I   Ignore case: GREP ignores upper/lowercase differences
        (case folding). GREP treats all letters a-z as being
        identical to the corresponding letters A-Z in all
        situations.

   -L   List match files: Only the name of each file containing a
        match is printed. After GREP finds a match, it prints the
        file name and processing immediately moves on to the next
        file.

   -N   Numbers: Each matching line that GREP prints is preceded
        by its line number.

   -O   UNIX output format: Changes the output format of matching
        lines to support more easily the UNIX style of
        command-line piping. All lines of output are preceded by
        the name of the file which contained the matching line.

   -R   Regular expression search: The text defined by
        searchstring is treated as a regular expression instead
        of as a literal string.

   -U   Update options: GREP will combine the options given on
        the command line with its default options and write these
        to the GREP.COM file as the new defaults. (In other
        words, GREP is self-configuring.) This option allows you
        to tailor the default option settings to your own taste.

   -V   Non-match: Only non-matching lines are printed. Only
        lines that do not contain the search string are
        considered to be non-matching lines.

   -W   Word search: Text found which matches the regular
        expression will be considered a match only if the
        character immediately preceding and following cannot be
        part of a word. The default word character set includes
        A-Z, 9-0, and the underbar (_). An alternate form of this
        option allows you to specify the set of legal word
        characters. Its form is -W[set], where set is any valid
        regular expression set definition. If alphabetic
        characters are used to define the set, the set will
        automatically be defined to contain both the upper and
        lower case values for each letter in the set, regardless
        of how it is typed, even if the search is case-sensitive.
        If the -W option is used in combination with the -U
        option, the new set of legal characters is saved as the
        default set.

   -Z   Verbose: GREP prints the file name of every file
        searched. Each matching line is preceded by its line
        number. A count of matching lines in each file is given,
        even if the count is zero.

Several of these options are in direct conflict with each other.
In these cases, the following order applies (the first one is the
one that takes precedence):

   -Z   -L   -C   -N

Each occurrence of an option overrides the previous definition:
Its state reflects the way you last set it. At any given time,
each option can only be on or off.

You can install your preferred default setting for each option in
GREP.COM with the -U option. For example, if you want GREP to
always do a verbose search (-Z on), you can install it with the
following command:

   GREP -U -Z


 How to Search Using GREP
==========================

The value of searchstring defines the pattern GREP will search
for.  A search string can be either a (via the -R switch) or a
literal string. In regular expressions, operators govern the
search; literal strings have no operators.

You can enclose the search string in quotation marks to prevent
spaces and tabs from being treated as delimiters. Matches will
not cross line boundaries (a match must be contained in a single
line).

When the -R switch is used, the search string is treated as a
regular expression (as opposed to a literal expression), and the
following symbols take on special meanings:

   ^   A caret at the start of the expression matches the start
       of a line.

   $   A dollar sign at the end of the expression matches the end
       of a line.

   .   A period matches any character.

   *   An expression followed by an asterisk wildcard matches
       zero or more occurrences of that expression: fo* matches
       f, fo, foo, etc.

   +   An expression followed by a plus sign matches one or more
       occurrences of that expression: fo+ matches fo, foo, etc.,
       but not f.

   []  A string enclosed in brackets matches any character in
       that string, but no others. If the first character in the
       string is a caret (^), the expression matches any
       character except the characters in the string. For
       example, [xyz] matches x, y, and z, while [^xyz] matches a
       and b, but not x or y. A range of characters can be
       specified by two characters separated by a hyphen (-).
       These can be combined to form expressions like [?a-bd-z]
       to match ? and any letter except c.

   \   The backslash "escape character" tells GREP to search for
       the literal character that follows it. For example, \.
       matches a period instead of any character.

   Note: Four characters (?, +, *, and .) do not have any special
   meaning when used in a set. The character ^ is only treated
   specially if it immediately follows the beginning of the set
   (that is, immediately after the [).

Any ordinary character not mentioned in this list matches that
character. A concatenation of regular expressions is a regular
expression.


 Examples Using GREP
=====================

The following examples assume all options default to off.

----------------------------------------------------------------

Search String   grep -n function dirdemo.pas

Finds       File DIRDEMO.PAS:
            51        LessFunc = function(X, Y: DirPtr): Boolean;
            60      function NumStr(N, D: Integer): String;
            73      function LessName(X, Y: DirPtr): Boolean;
            78      function LessSize(X, Y: DirPtr): Boolean;
            83      function LessTime(X, Y: DirPtr): Boolean;

Remarks     Finds all functions in the file DIRDEMO.PAS. The -N
            tells GREP to precede each matched line with its line
            number.

-----------------------------------------------------------------

Search String   grep {\$ dirdemo.pas

Finds       File DIRDEMO.PAS:
            {$I-,S-}
            {$M 8192,8192,655360}
            {$F+}
            {$F-}

Remarks     Finds all compiler directives in DIRDEMO.PAS. The \
            (backslash) preceding the $ is necessary. Without it,
            the $ would indicate the end of the line. All lines
            with { (curly bracket) as the last character would
            match this pattern and be printed out.

-----------------------------------------------------------------

Search String   grep -i "^ *function.*).*real" *.pas

Finds       File WORKERS.PAS:
            function RoundPay(Wages: Real): Real;

Remarks     Finds all lines that begin with zero or more spaces
            followed by the word function, followed by any string
            of zero or more characters, followed by a
            parenthesis, followed by another string of zero or
            more characters, followed by the word Real, and
            ignores case. The net effect is to search for all
            functions returning a Real. See if you can think of
            other ways to do this.

            The double quotes are necessary because of the space
            in the pattern string. The quotes tell the DOS
            command-line processor to treat the intervening
            characters as a single argument. Without the quotes,
            DOS will think the search string is actually two
            arguments, and GREP will think that everything after
            ^ (the caret character) refers to file names, and
            will complain

            No files matching: *FUNCTION.*).*.


=======================
 3. The BINOBJ Utility
=======================

A utility program called BINOBJ.EXE has been added to convert any
file to an .OBJ file so it can be linked into a pascal program as
a "procedure." This is useful if you have a binary data file that
must reside in the code segment or is too large to make into a
typed constant array. For example, you can use BINOBJ with the
Graph unit to link the graphics driver or font files directly
into your .EXE file. Then, to use your graph program, you need
only have the .EXE file (see the example BGILINK.PAS).

BINOBJ takes three parameters:

   BINOBJ  <source[.BIN]>  <destination[.OBJ]>  <public name>

where source is the binary file to convert, destination is the
name of the .OBJ to be produced, and public name is the name of
the procedure as it will be declared in your pascal program.

The following example, the procedure ShowScreen, takes a pointer
as a parameter and moves 4000 bytes of data to screen memory. The
file called MENU.DTA contains the image of the main menu screen
(80 * 25 * 2 = 4000 bytes).

Here's a simple (no error-checking) version of MYPROG.PAS:

   program MyProg;

   uses Crt;

   procedure ShowScreen(ScreenData : Pointer);
   { Display a screenful of data--no error-checking! }
   var
     ScreenSegment: Word;

   begin
     if (Lo(LastMode) = 7) then      { Mono? }
       ScreenSegment := $B000
     else
       ScreenSegment := $B800;
     Move(ScreenData^,               { From pointer }
      Ptr(ScreenSegment, 0)^,        { To video memory }
      4000);                         { 80 * 25 * 2 }
   end;

   var
     MenuP : Pointer;
     MenuF : file;
   begin
     Assign(MenuF, 'MENU.DTA');      { Open screen data file }
     Reset(MenuF, 1);
     GetMem(MenuP, 4000);            { Allocate buffer on heap }
     BlockRead(MenuF, MenuP^, 4000); { Read screen data }
     Close(MenuF);
     ShowScreen(MenuP);              { Display screen }
   end.


The screen data file (MENU.DTA) is opened and then read into a
buffer on the heap. Both MYPROG.EXE and MENU.DTA must be present
at run-time for this program to work. You can use BINOBJ to
convert MENU.DTA to an .OBJ file (MENUDTA.OBJ) and tell it to
associate the data with a procedure called MenuData. Then you can
declare the fake external procedure MenuData, which actually
contains the screen data. Once you link in the .OBJ file with the
$L compiler directive, MenuData will be 4000 bytes long and
contain your screen data. First, run BINOBJ on MENU.DTA:

   binobj MENU.DTA MENUDTA MenuData

The first parameter, MENU.DTA, shows a familiar file of screen
data; the second, MENUDTA, is the name of the .OBJ file to be
created (since you didn't specify an extension, .OBJ will be
added). The last parameter, MenuData, is the name of the external
procedure as it will be declared in your program. Now that you've
converted MENU.DTA to an .OBJ file, here's what the new
MYPROG.PAS looks like:

   program MyProg;

   uses Crt;

   procedure ShowScreen(ScreenData : Pointer);
   { Display a screenful of data--no error checking! }
   var
     ScreenSegment: Word;
   begin
     if (Lo(LastMode) = 7) then             { Mono? }
       ScreenSegment := $B000
     else
       ScreenSegment := $B800;
     Move(ScreenData^,                      { From pointer }
      Ptr(ScreenSegment, 0)^,               { To video memory }
      4000);                                { 80 * 25 * 2 }
   end;

   procedure MenuData; external;
   {$L MENUDTA.OBJ }
   begin
     ShowScreen(@MenuData);                 { Display screen }
   end.

Notice that ShowScreen didn't change at all, and that the ADDRESS
of your procedure is passed using the @ operator.

===================================
 4. Using TPUMOVER, the Unit Mover
===================================

When you write units, you want to make them easily available to any
programs that you develop. We'll now show you how to use TPUMOVER to
remove seldom-used units from TURBO.TPL, and how to insert often-used
units into TURBO.TPL.


 A Review of Unit Files
========================

There are two types of unit files: .TPU files and .TPL files. When you
compile a unit, Turbo Pascal puts the resulting object code in a .TPU
(Turbo Pascal Unit) file, which always contains exactly one unit.

A .TPL (Turbo Pascal Library) file, on the other hand, can contain multiple
units. For example, several units that come on your Turbo Pascal disks
are in the file TURBO.TPL. The file TURBO.TPL is currently the only
library file Turbo Pascal will load units from.

You may have noticed, though, that you can use the standard Turbo Pascal
units without giving a file name. That's because these units are stored in
the Turbo Pascal standard unit file--TURBO.TPL on your distribution disk.
Because the units are in that file, any program can use them without
"knowing" their location.

Suppose you have a unit called TOOLS.TPU, and you use it in many different
programs. Though adding Tools to TURBO.TPL takes up memory (TURBO.TPL is
automatically loaded into memory by the compiler), adding it to the
resident library makes "using" Tools faster because the unit is in memory
instead of on disk.

There are five standard units already in TURBO.TPL: System, Overlay,
Printer, Crt, and Dos.


 Using TPUMOVER
================

You can use several command-line parameters that let you manipulate units
quickly. The syntax for these parameters is

   TPUMOVER filename operations

where filename is either a .TPU file or a .TPL file,
      and operations is an optional list of one or more of the following
      commands:

         +unitname    Add a unit to the library.
         -unitname    Delete a unit from the library.
         *unitname    Extract a unit from the library.

If no operations are specified, TPUMOVER lists the units in the library
file along with size and dependency information.


=================================
 5. The Stand-Alone MAKE Utility
=================================

This section contains complete documentation for creating makefiles and
using MAKE.


 Creating Makefiles
====================

A makefile contains the definitions and relationships needed to help MAKE
keep your program(s) up to date. You can create as many makefiles as you
want and name them whatever you want. If you don't specify a makefile when
you run MAKE (using the -f option), then MAKE looks for a file with the
default name MAKEFILE.

You create a makefile with any ASCII text editor, such as Turbo Pascal's
built-in interactive editor. All rules, definitions, and directives end
with a carriage return; if a line is too long, you can continue it to the
next line by placing a backslash (\) as the last character on the line.

Whitespace--spaces and tabs--is used to separate adjacent identifiers (such
as dependencies) and to indent commands within a rule.

Creating a makefile is almost like writing a program--with definitions,
commands, and directives.

 Comments
----------

Comments begin with a number sign (#); the rest of the line following the #
is ignored by MAKE. Comments can be placed anywhere and never have to start
in a particular column.


 Explicit Rules
----------------

Explicit rules take the form

   target [target ... ]: [source source ... ]
      [command]
      [command]
      ...

where target is the file to be updated, source is a file upon which target
depends, and command is any valid MS-DOS command (including invocation of
.BAT files and execution of .COM and .EXE files).

Explicit rules define one or more target names, zero or more source files,
and an optional list of commands to be performed. Target and source file
names listed in explicit rules can contain normal MS-DOS drive and
directory specifications, but they cannot contain wildcards.

Syntax here is important. target must be at the start of a line (in column
1), and each command must be indented (preceded by at least one space
character or tab). As mentioned before, the backslash (\) can be used as a
continuation character if the list of source files or a given command is
too long for one line. Finally, both the source files and the commands are
optional; it is possible to have an explicit rule consisting only of

   target [target ...] followed by a colon.

The idea behind an explicit rule is that the command or commands listed
will create or update target, usually using the source files. When MAKE
encounters an explicit rule, it first checks to see if any of the source
files are target files elsewhere in the makefile. If so, those rules are
evaluated first.

Once all the source files have been created or updated based on other
explicit (or implicit) rules, MAKE checks to see if target exists. If not,
each command is invoked in the order given. If target does exist, its time
and date of last modification are compared against the time and date for
each source. If any source has been modified more recently than target, the
list of commands is executed.

A given file name can occur on the left side of an explicit rule only once
in a given execution of MAKE.

Each command line in an explicit rule begins with whitespace. MAKE
considers all lines following an explicit rule to be part of the command
list for that rule, up to the next line that begins in column 1 (without
any preceding whitespace) or up to the end of the file. Blank lines are
ignored.

An explicit rule, with no command lines following it, is treated a little
differently than an explicit rule with command lines.

   o If an explicit rule exists for a target with commands, the only files
     that the target depends on are the ones listed in the explicit rule.

   o If an explicit rule has no commands, the targets depend on the files
     given in the explicit rule, and they also depend on any file that
     matches an implicit rule for the target(s).

Here are some examples of explicit rules from a makefile:

   myutil.obj: myutil.asm
     tasm myutil.asm,myutil.obj;

   myapp.exe:  myapp.pas myglobal.tpu myutils.tpu
     tpc myapp /Tc:\tp5\bin

   o The first explicit rule states that MYUTIL.OBJ depends upon
     MYUTIL.ASM, and that MYUTIL.OBJ is created by executing the given
     TASM command.

   o The second rule states that MYAPP.EXE depends upon MYAPP.PAS,
     MYGLOBAL.TPU, and MYUTILS.TPU, and is created by the given TPC
     command. (The /T plus path name in these examples will be explained
     later.)

If you reorder the rules so that the one for MYAPP.EXE comes first,
followed by the others, MAKE will recompile (or reassemble) only the files
that it has to in order to update everything correctly. This is because a
MAKE with no target on the command line will try to execute the first
explicit rule it finds in the makefile.


 Implicit Rules
----------------

MAKE also allows you to define implicit rules, which are generalizations of
explicit rules. Here's an example to illustrate the relationship between
the two types. Consider this explicit rule from the previous sample
program:

   myutil.obj: myutil.asm
     tasm myutil.asm,myutil.obj;

This rule is a common one, because it follows a general principle: An .OBJ
file is dependent on the .ASM file with the same file name and is created
by executing TASM (Turbo Assember). In fact, you might have a makefile
where you have several (or even several dozen) explicit rules following
this same format.

By redefining the explicit rule as an implicit rule, you can eliminate all
the explicit rules of the same form. As an implicit rule, it would look
like this:

   .asm.obj:
     tasm $*.asm,$*.obj;

This rule means, "any file ending with .OBJ depends on the file with the
same name that ends in .ASM, and the .OBJ file is created using the command

   tasm $*.asm,$*.obj

where $* represents the file's name with no extension." (The symbol $* is a
special macro and is discussed in the next section.)

The syntax for an implicit rule follows:

   .source_extension.target_extension:
     {command}
     {command}
     ...

Note the commands are optional and must be indented. The source_extension
(which must begin in column 1) is the extension of the source file, that
is, it applies to any file having the format

   fname.source_extension

Likewise, the target_extension refers to the the file

   fname.target_extension

where fname is the same for both files. In other words, this implicit rule
replaces all explicit rules having the format

   fname.target_extension:fname.source_extension
     [command]
     [command]
     ...

for any fname.

Implicit rules are used if no explicit rule for a given target can be found
or if an explicit rule with no commands exists for the target.

The extension of the file name in question is used to determine which
implicit rule to use. The implicit rule is applied if a file is found with
the same name as the target, but with the mentioned source extension. For
example, suppose you had a makefile (named MAKEFILE) whose contents were

   .asm.obj:
     tasm $*.asm,$*.obj;

If you had an assembly language routine named RATIO.ASM that you wanted to
compile to RATIO.OBJ, you could use the command

   make ratio.obj

MAKE would take RATIO.OBJ to be the target and create it by executing the
command:

   tasm ratio.asm,ratio.obj;

Implicit rules are also used if an explicit rule is given with no commands.
Suppose, as mentioned before, you had the following implicit rule at the
start of your makefile:

   .pas.tpu:
     tpc $<

You could then rewrite some explicit rules as follows:

   myglobal.tpu: myglobal.pas
   myutils.tpu: myutils.pas myglobal.tpu myutil.obj

Since you don't have explicit information on how to create these .TPU
files, MAKE applies the implicit rule defined earlier.

Several implicit rules can be written with the same target extension, but
only one such rule can apply at a time. If more than one implicit rule
exists for a given target extension, each rule is checked in the order the
rules appear in the makefile, until all applicable rules are checked.

MAKE uses the first implicit rule that it discovers for a file with the
source extension. Even if the commands of that rule fail, no more implicit
rules are checked.

All lines following an implicit rule are considered to be part of the
command list for the rule, up to the next line that begins without
whitespace or to the end of the file. Blank lines are ignored. The syntax
for a command line is provided later in this appendix.

MAKE does not know the full file name with an implicit rule, as it does
with explicit rules. For that reason, special macros are provided with MAKE
that allow you to include the name of the file being built by the rule.


 Command Lists
---------------

Commands in a command list must be indented--that is, preceded by at least
one space character or tab--and take the form

   [ prefix ... ] command_body

Each command line in a command list consists of an (optional) list of
prefixes, followed by a single command body.

The prefixes allowed in a command modify the treatment of these commands by
MAKE. The prefix is either the at (@) sign or a hyphen (-) followed
immediately by a number.

   @   Keeps MAKE from displaying the command before executing it. The
       display is hidden even if the -s option was not given on the MAKE
       command line. This prefix applies only to the command on which it
       appears.

   -num   Affects how MAKE treats exit codes. If a number (num) is
          provided, then MAKE will abort processing only if the exit status
          exceeds the number given. In this example, MAKE will abort only
          if the exit status exceeds 4:

             -4 myprog sample.x

          If no -num prefix is given, MAKE checks the exit status for the
          command. If the status is nonzero, MAKE will stop and delete the
          current target file.

   -   With a hyphen but no number, MAKE will not check the exit status at
       all. Regardless of what the exit status was, MAKE will continue.

The command body is treated exactly as if it were entered as a line to
COMMAND.COM, with the exception that redirection and pipes are not
supported. MAKE executes the following built-in commands by invoking a copy
of COMMAND.COM to perform them:

   BREAK      CD      CHDIR      CLS      COPY
   MD         MKDIR   PATH       PROMPT   REN
   RENAME     SET     TIME       TYPE     VER
   VERIFY     VOL

MAKE searches for any other command name using the MS-DOS search algorithm:

   o The current directory is searched first, followed by each directory
     in the path.

   o In each directory, first a file with the extension .COM is checked,
     then an .EXE file, and finally a .BAT.

   o If a .BAT file is found, a copy of COMMAND.COM is invoked to execute
     the batch file.


This command will cause MYPROG.PAS to be searched for, using the full
search algorithm:

   tpc myprog.pas /$B+,R+,I+


 Macros
--------

Often certain commands, file names, or options are used again and again in
your makefile. In an example earlier in this appendix, all the TPC commands
used the switch /Tc:\tp5\bin, which means that the files TPC.CFG and
TURBO.TPL are in the subdirectory C:\TP5\BIN. Suppose you wanted to switch
to another subdirectory for those files; what would you do? You could go
through and modify all the /T options, inserting the appropriate path name.
Or, you could define a macro.

A macro is a name that represents some string of characters (letters and
digits). A macro definition gives a macro name and the expansion text;
thereafter, when MAKE encounters the macro name, it replaces the name with
the expansion text.

Suppose you defined the following macro at the start of your makefile:

   TURBO=c:\tp5\bin

You've defined the macro TURBO, which is equivalent to the string
c:\tp5\bin. You could now rewrite the makefile as follows:

   TURBO=c:\tp5\bin
   myapp.exe:  myapp.pas myglobal.tpu myutils.tpu
     tpc myapp /T$(TURBO)

   myutils.tpu: myutils.pas myglobal.tpu myutil.obj
     tpc myutils /T$(TURBO)


Everywhere the Turbo directory is specified, you use the macro invocation
$(TURBO). When you run MAKE, $(TURBO) is replaced with its expansion text,
c:\TP5.BIN. The result is the same set of commands you had before but with
greater flexibility.

In fact, if you leave out the first line altogether, you can specify which
subdirectory you want each time you run MAKE, using the -D (Define) option:

   make -DTURBO=c:\tp5\project

Macro definitions take the form

   macro_name=expansion text

where macro_name is the name of a macro made up of a string of letters and
digits with no whitespace in it, though you can have whitespace between
macro_name and the equal sign (=). [expansion text] is any arbitrary string
containing letters, digits, whitespace, and punctuation; it is ended by a
carriage return.  Note that macros are case sensitive.  Thus the macro
names Turbo, turbo and TURBO are all different.

If macro_name has previously been defined, either by a macro definition in
the makefile or by the -D option on the MAKE command line, the new
definition replaces the old.

Macros are invoked in your makefile with the format

   $(macro_name)

Macros in macros: Macros cannot be invoked on the left (macro_name) side of
a macro definition. They can be used on the right (expansion text) side,
but they are not expanded until the macro being defined is invoked. In
other words, when a macro invocation is expanded, any macros embedded in
its expansion text are also expanded.

MAKE comes with several special predefined macros built-in: $d, $*, $<, $:,
$., and $&. The first is a defined test macro, used in the conditional
directives !if and !elif; the others are file name macros, used in explicit
and implicit rules. The various file name macros work in similar ways,
expanding to some variation of the full path name of the file being built.
In addition, the current SET environment strings are automatically loaded
as macros, and the macro __MAKE__ is defined to be 1 (one).


 Defined Test Macro ($d)

This macro expands to 1 if the given macro name is defined, or to 0 if it
is not. The content of the macro's expansion text does not matter. This
special macro is allowed only in !if and !elif directives. For example, if
you wanted to modify your makefile so that it would use a particular Turbo
Pascal directory if you didn't specify one, you could put this at the start
of your makefile:

   !if !$d(TURBO)            # if TURBO is not defined
   TURBO=c:\tp5\bin          # define it to C:\TP5\BIN
   !endif

If you invoke MAKE with the command line

   make -DTURBO=c:\tp5\project

then TURBO is defined as c:\tp5\project. If, however, you just invoke MAKE
by itself,

   make

then TURBO is defined as c:\tp5\bin, your "default" subdirectory.


 Base File Name Macro ($*)

This macro is allowed in the commands for an explicit or an implicit rule.
The macro expands to the file name being built, excluding any extension,
like this:

   File name is A:\P\TESTFILE.PAS
   $* expands to A:\P\TESTFILE

For example, you could modify the explicit MYAPP.EXE rule already given to
look like this:

   myapp.exe:  myapp.pas myglobal.tpu myutils.tpu
     tpc $* /T$(TURBO)


 Full File Name Macro ($<)

The full file name macro ($<) is also used in the commands for an explicit
or implicit rule. In an explicit rule, $< expands to the full target file
name (including extension), like this:

   File name is A:\P\TESTFILE.PAS
   $< expands to A:\P\TESTFILE.PAS

In an implicit rule, $< takes on the file name plus the source extension.
For example, the previous implicit rule

   .asm.obj:
     tasm $*.asm,$*.obj;

can be rewritten as

   .asm.obj:
      tasm $<,$*.obj;


 File Name Path Macro ($:)

This macro expands to the path name (without the file name), like this:

   File name is A:\P\TESTFILE.PAS
   $: expands to A:\P\


 File Name and Extension Macro ($.)

This macro expands to the file name, with extension, like this:

   File name is A:\P\TESTFILE.PAS
   $. expands to TESTFILE.PAS


 File Name Only Macro ($&)

This macro expands to the file name only, without path or extension, like
this:

   File name is A:\P\TESTFILE.PAS
   $& expands to TESTFILE


 Directives
------------

The version of MAKE bundled with Turbo Pascal allows something that other
versions of MAKE don't: conditional directives similiar to those allowed
for Turbo Pascal. You can use these directives to include other makefiles,
to make the rules and commands conditional, to print out error messages,
and to "undefine" macros.

Directives in a makefile begin with an exclamation point (!). Here is the
complete list of MAKE directives:

   !include
   !if
   !else
   !elif
   !endif
   !error
   !undef

A file-inclusion directive (!include) specifies a file to be included into
the makefile for interpretation at the point of the directive. It takes the
following form:

   !include "filename"

or

   !include <filename>

These directives can be nested arbitrarily deep. If an include directive
attempts to include a file that has already been included in some outer
level of nesting (so that a nesting loop is about to start), the inner
include directive is rejected as an error.

Conditional directives (!if, !elif, !else, and !endif) give a programmer a
measure of flexibility in constructing makefiles. Rules and macros can be
"conditionalized" so that a command-line macro definition (using the -D
option) can enable or disable sections of the makefile.

The format of these directives parallels, but is more extensive than, the
conditional directives allowed by Turbo Pascal:

   !if expression
     [ lines ]
   !endif

   !if expression
     [ lines ]
   !else
     [ lines ]
   !endif

   !if expression
     [ lines ]
   !elif expression
     [ lines ]
   !endif

The conditional directives form a group, with at least an !if directive
beginning the group and an !endif directive closing the group.

The expression allowed in an !if or an !elif directive uses a syntax
similar to that found in the C programming language. The expression is
evaluated as a simple 32-bit signed integer expression.

Numbers can be entered as decimal, octal, or hexadecimal constants. For
example, these are legal constants in an expression:

   4536       # decimal constant
   0677       # octal constant (note the leading zero)
   0x23aF     # hexadecimal constant

and any of the following unary operators:

   -     negation
   ~     bit complement
   !     logical not

An expression can use any of the following binary operators:

   +     addition
   -     subtraction
   *     multiplication
   /     division
   %     remainder
   >>    right shift
   <<    left shift
   &     bitwise and
   |     bitwise or
   ^     bitwise exclusive or
   &&    logical and
   ||    logical or
   >     greater than
   <     less than
   >=    greater than or equal to
   <=    less than or equal to
   ==    equality
   !=    inequality

An expression can contain the following ternary operator:

   ? :   The operand before the ? is treated as a test.

         If the value of that operand is nonzero, then the second
         operand (the part between the ? and the colon) is the
         result. If the value of the first operand is zero, the
         value of the result is the value of the third operand
         (the part after the :).

Parentheses can be used to group operands in an expression. In the absence
of parentheses, binary operators are grouped according to the same
precedence given in the C language.

Grouping is from left to right for operators of equal precedence, except
for the ternary operator (? :), which is right to left.

Macros can be invoked within an expression, and the special macro $d() is
recognized. After all macros have been expanded, the expression must have
proper syntax. Any words in the expanded expression are treated as errors.

The error directive (!error) causes MAKE to stop and print a fatal
diagnostic containing the text after !error. It takes the format

   !error [any_text]

This directive is designed to be included in conditional directives to
allow a user-defined abort condition.

The undefine directive (!undef) causes any definition for the named macro
to be forgotten. If the macro is currently undefined, this directive has no
effect.

 Using MAKE
============

You now know a lot about how to write makefiles; now's the time to learn
how to use them with MAKE. The simplest way to use MAKE is to type the
command

   MAKE

at the MS-DOS prompt. MAKE then looks for MAKEFILE; if it can't find it, it
looks for MAKEFILE.MAK; if it can't find that, it halts with an error
message.

You can specify a file with the -f option:

   MAKE -fstars.mak

The general syntax for MAKE is

   make option option ... target target ...

where option is a MAKE option (discussed later) and target is the name of a
target file to be handled by explicit rules.

If the command line does not include any target names, MAKE uses the first
target file mentioned in an explicit rule. If one or more targets are
mentioned on the command line, they will be built as necessary.

Here are some more examples of MAKE command lines:

   make -n -fstars.mak
   make -s
   make -Iinclude -DTURBO=c:\tp5\project


 The BUILTINS.MAK File
-----------------------

As you become familiar with MAKE, you will find that there are macros and
rules (usually implicit ones) that you use again and again. You've got
three ways of handling them. First, you can put them in every makefile you
create. Second, you can put them all in one file and use the !include
directive in each makefile you create. Third, you can put them all in a
file named BUILTINS.MAK.

Each time you run MAKE, it looks for a file named BUILTINS.MAK; if it finds
the file, MAKE reads it in before handling MAKEFILE (or whichever makefile
you want it to process).

The BUILTINS.MAK file is intended for any rules (usually implicit rules) or
macros that will be commonly used in files anywhere on your computer.

There is no requirement that any BUILTINS.MAK file exist. If MAKE finds a
BUILTINS.MAK file, it interprets that file first. If MAKE cannot find a
BUILTINS.MAK file, it proceeds directly to interpreting MAKEFILE (or
whatever makefile you specify).


 How MAKE Searches for Files
-----------------------------

MAKE will search for BUILTINS.MAK in the current directory or in the exec
directory if your computer is running under DOS 3.x. You should place this
file in the same directory as the MAKE.EXE file.

MAKE always searches for the makefile in the current directory only. This
file contains the rules for the particular executable program file being
built. The two files have identical syntax rules.

MAKE also searches for any !include files in the current directory. If you
use the -I (Include) option, it will also search in the specified
directory.


 MAKE Command-Line Options
---------------------------

   -Didentifier   Defines the named identifier to the string consisting of
                  the single character 1.

   -Diden=string  Defines the named identifier iden to the string after
                  the equal sign. The string cannot contain any spaces or
                  tabs.

   -Idirectory    MAKE will search for include files in the indicated
                  directory (as well as in the current directory).

   -Uidentifier   Undefines any previous definitions of the named
                  identifier.

   -s             Normally, MAKE prints each command as it is about to be
                  executed. With the -s option, no commands are printed
                  before execution.

   -n             Causes MAKE to print the commands, but not actually
                  perform them. This is useful for debugging a makefile.

   -ffilename     Uses filename as the MAKE file. If filename does not
                  exist and no extension is given, tries filename.MAK.

   -? or -h       Prints help message.


 MAKE Error Messages
---------------------

 Fatal Errors

Don't know how to make XXXXXXXX
   This message is issued when MAKE encounters a nonexistent file name in
   the build sequence, and no rule exists that would allow the file name to
   be built.

Error directive: XXXX
   This message is issued when MAKE processes an #error directive in the
   source file. The text of the directive is displayed in the message.

Incorrect command line argument: XXX
   This error occurs if MAKE is executed with incorrect command-line
   arguments.

Not enough memory
   This error occurs when the total working storage has been exhausted. You
   should try this on a machine with more memory. If you already have 640K
   in your machine, you may have to simplify the source file.

Unable to execute command
   This message is issued after attempting to execute a command. This could
   be a result of the command file not being found, or because it was
   misspelled. A less likely possibility is that the command exists but is
   somehow corrupted.

Unable to open makefile
   This message is issued when the current directory does not contain a
   file named MAKEFILE.


 Errors

Bad file name format in include statement
   Include file names must be surrounded by quotes or angle brackets. The
   file name was missing the opening quote or angle bracket.

Bad undef statement syntax
   An !undef statement must contain a single identifier and nothing else as
   the body of the statement.

Character constant too long
   Character constants can be only one or two characters long.

Command arguments too long
   The arguments to a command executed by MAKE were more than 127
   characters--a limit imposed by DOS.

Command syntax error
   This message occurs if

      o the first rule line of the makefile contained any leading
        whitespace.

      o an implicit rule did not consist of .ext.ext:.

      o an explicit rule did not contain a name before the : character.

      o a macro definition did not contain a name before the = character.

Division by zero
   A divide or remainder in an !if statement has a zero divisor.

Expression syntax error in !if statement
   The expression in an !if statement is badly formed--it contains a
   mismatched parenthesis, an extra or missing operator, or a missing or
   extra constant.

File name too long
   The file name given in an !include directive was too long for MAKE to
   process. File path names in MS-DOS must be no more than 78 characters
   long.

Illegal character in constant expression X
   MAKE encountered some character not allowed in a constant expression. If
   the character is a letter, this indicates a (probably) misspelled
   identifier.

Illegal octal digit
   An octal constant was found containing a digit of 8 or 9.

Macro expansion too long
   A macro cannot expand to more than 4096 characters. This error often
   occurs if a macro recursively expands itself. A macro cannot legally
   expand to itself.

Misplaced elif statement
   An !elif directive was encountered without any matching !if directive.

Misplaced else statement
   An !else directive was encountered without any matching !if directive.

Misplaced endif statement
   An !endif directive was encountered without any matching !if directive.

No file name ending
   The file name in an include statement was missing the correct closing
   quote or angle bracket.

Redefinition of target XXXXXXXX
   The named file occurs on the left-hand side of more than one explicit
   rule.

Unable to open include file XXXXXXXXX.XXX
   The named file could not be found. This could also be caused if an
   include file included itself. Check whether the named file exists.

Unexpected end of file in conditional started on line #
   The source file ended before MAKE encountered an !endif. The !endif was
   either missing or misspelled.

Unknown preprocessor statement
   A ! character was encountered at the beginning of a line, and the
   statement name following was not error, undef, if, elif, include, else,
   or endif.


*  *  *  *  *