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/*************************************************************************
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|   PAMAKE.DOC Version  1.80                                    30.09.89 |
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|   PAMAKE Documentation (c) 1988-9 Roundhill Computer Systems Limited   |
|                                                                        |
*************************************************************************/

Introduction
============

PAMAKE is a `free' utility distributed with Roundhill's PANEL Plus II screen
management product.  This is the documentation file for PAMAKE.

This program was originally based on Neil Russell's public domain make utility,
but has been extensively rewritten and enhanced for use with PANEL Plus II.

PAMAKE is distributed without any warranty of any kind, either expressed or
implied.  Neither the authors nor anyone else who has been involved in the
creation, production or delivery of this program shall be liable for any
direct, indirect, consequential or incidental damages arising out of the use
of, or inability to use, this program.

Roundhill Computer Systems claims no rights to the PAMAKE source code or to
the name `PAMAKE', but this documentation file is Copyright (c) 1988, 1989
Roundhill Computer Systems Limited.  Permission is granted to reproduce the
text of this file in connexion with personal use of PAMAKE.  We respectfully
ask that if you modify the PAMAKE source code and then re-publish the source
code, you should use a name other than `PAMAKE' to identify it, and write your
own documentation for it.  We do not authorise the distribution or publishing
of this copyright documentation file except when it accompanies the unmodified
complete source of PAMAKE.  Alternatively, if you tell us about changes and
enhancements you make, we would be pleased to consider incorporating them them
in a future version.  That way everyone can benefit from all the enhancements.

History
=======

In the first releases of PANEL Plus we distributed a `makefile' with each set
of compiler-specific files.  We deliberately included the actual makefile used
to build the library, so that there would be no possibility of sending out a
makefile which did not match the distribution libraries:  but the make utility
we were then using for development (Lattice Make (LMK)) has a lot of features
which are not supported by other `make' utilities so the makefiles often had
to be extensively adapted to run in user environments.

We then obtained a public domain make source and revised it with substantial
enhancements to meet the minimum requirements for our own development.  The
result was the PAMAKE program which is now included with the library source
for DOS, OS/2 and VMS versions of PANEL Plus to help to build the libraries,
and which we may supply in a future PANEL Plus release for other operating
systems also.

If the PAMAKE utility is used to build PANEL Plus II applications it should
only be necessary to make very small changes to the supplied makefiles to
customise them to specific develpment environments.

The source code for Neil Russell's make is available on BIX and elsewhere,
both in its original form and as modified by Cheyenne Wills and others.  The
source code for PAMAKE is also available on BIX as PAMAKEnn.ARC in the
"roundhill/listings" area.  The `nn' indicates the version number, for example
PAMAKE17 for version 1.7.

Version 1.3 changes:

    -  tidied the source code so that it compiles with only two warnings under
       Microsoft C version 5.1.

    -  added one more built-in macro, PAMAKE_OS, which currently can take the
       values "DOS", "OS2" or "VMS".  This allows makefiles to be used easily
       (with variations) in more than one environment.  We also made a VMS
       version, and added some notes about it below.

Version 1.4 changes:

    -  added a special expansion of $* as a dependency name.  Thanks to Erin
       McDonald for suggesting this enhancement.

Version 1.5 changes:

    -  fixed a problem involving the recursive application of dependency rules.
       Earlier versions would not apply a second dependency rule automatically
       if it took multiple steps to build a target and only the first file was
       present.  We also added the `%exit' special command, and the $(HOME)
       built-in macro, and made a default of `pamake' for the $(MAKE) macro.

Version 1.6 changes:

    -  added a test for selected DOS internal commands, and also command-line
       redirection.  Thanks to M. F. Winiberg for these suggestions.

    -  added a SIGINT trap.

    -  modified the source to build a `family' (DOS and OS/2 combined) version
       of PAMAKE using Lattice C, which is so much better at this task than
       you-know-who.  In the Lattice C version, all timestamps are held
       internally in `file time' format rather than `time_t' format.

Version 1.7 changes:

    - again fixed the problem with recursive application of dependency rules,
      which was not fully dealt with in 1.5.

    - removed the SIGINT function 'brk', which conflicts with a standard
      library name in the new VMS C version 3.0.  We have also found that
      trying to set BREAK ON causes problems with Lattice, so we removed
      that too.  We recommend setting BREAK ON to make it easier to break
      out of runaway make operations.

    - fixed a minor bug caused by the use of high-bit characters for `$*'
      processing: because they are not Ascii characters, ANSI specifies that
      the macro `isspace' returns an undefined value.  Also repaired the
      $? macro, which was broken.

    - the local input file processor now allows "\<" as a code to place a "<"
      in the file.  This allows recursive calling of PAMAKE using a local
      input file to create the makefile.

    - if a command cannot be executed, the target is now automatically made
      `precious'.  This prevents files being deleted for example if you make a
      mistake in your path setting.  The target is also forced to be precious
      if -n is used with a recursive call to pamake.

    - a new command-line switch, `-c', has been added to force a re-read
      of the file time after the commands to build it are complete.  This
      allows PAMAKE to respond correctly to commands such as ARC, which may
      leave the file time set to something different from the current time.

    - a new pseudo-command, `%stat' has been added to force a re-read of
      the file time of the filename following the command.  This allows PAMAKE
      to respond correctly if you use a command to delete or modify a file
      other than the current target.

Version 1.8 changes:

    - Fixed conditional processing which could still process text inside the
      `else' half of a true condition.

    - Added support for Borland Turbo C.  Tidied all the file time processing
      into a separate module `mtime.c'.

    - PAMAKE no longer ignores `interrupted' if the ignore flag is set.

PAMAKE enhancements
===================

The principal enhancements we needed to incorporate were the ability to set DOS
environment variables from within PAMAKE (which we require to handle the
different environment settings of the many compilers we support with PANEL Plus
II), the ability to support development when the source files are in one
subdirectory and the objects and libraries are in another, support for include
files and conditional execution, and a `local input file' feature.  Some of the
features require considerable changes to the way inference rules and special
macros are processed, but the result is as compatible with Unix make as
possible.

The `local input file' allows link and library command files to be set up
dynamically (and macro-expanded).  This feature ensures that all the commands
to build a project can be included in one makefile, and avoids having to use
the DOS echo command (with a consequent reduction in efficiency).

The operation of PAMAKE is closely modelled on the Unix `make', and in
particular is completely different from the operation of the make utility
supplied with Microsoft C version 5.1.  The latter requires commands to be
listed in execution sequence, and then applies the normal dependency tests to
decide whether to execute each one.  In contrast PAMAKE requires the principal
target to be listed first (or named on the command line) and recursively tests
all the other makefile statements to determine automatically the particular
commands to execute and their sequence.

Using PAMAKE
============

The command line syntax can be determined by executing:

            PAMAKE -?

and the built-in macros, rules and suffixes by executing:

            PAMAKE -f - -p <NUL

This documentation file contains full details of the PAMAKE enhancements, and
a brief summary of the principles of operation of a traditional Unix make
utility.  For a full explanation of the operation of a `make' you are referred
to a standard Unix reference manual.  The principal make features not currently
included in PAMAKE are the following:                             ~~~

    - The $% special macro [library member name]
    - The D and F special macro modifiers [directory part and file part]
    - SCCS file and archive file support
    - The -k and -b command-line switches
    - There are no built-in macros such as CC=cc

PAMAKE special features
=======================

Enhancements in PAMAKE and differences from Unix `make' include the following:

    - If a macro name begins with `+' then the `+' is removed and the macro
      definition is also placed in the `environment' for the commands executed
      by PAMAKE.  This feature allows setting of command paths, include file
      paths, and special compiler environment variable switches automatically,
      instead of in an AUTOEXEC file or manually.  Nested macros in the
      environment variable value are expanded at the time it is defined, that
      is once, when the macro is first processed.  If the macro is also used
      as a regular macro any nested macros are expanded in the normal way at
      the time the macro is used.  Macro names starting with `+' are placed
      in the execution environment even if the -e switch prevents their
      overriding a macro definition of the same name already present in the
      initial environment.  This feature is not supported in VMS: if a macro
      name begins with `+' the `+' is ignored.

    - Whitespace is deleted between a macro definition and a comment starting
      with #.  This makes it much easier to document makefiles.  Many Unix
      `makes' do not do this.

    - If a command line starts with `+' then it is invoked using a `system'
      function instead of being spawned directly.  This enables internal DOS
      commands to be used.  The most often used DOS and OS/2 commands are
      also detected automatically.  Currently this list includes ECHO, DEL,
      ERASE, MD, MKDIR, REN, RENAME and COPY.  If you need other DOS commands,
      you should either use `+' or modify the source.  No DOS error code is
      available from commands executed through the `system' function, but OS/2
      does pass back error information.  Currently, the VMS version always
      uses the `system' call to spawn programs.

    - PAMAKE handles redirection for commands not executed through `system'.
      The symbols processed are "<", ">", ">>", "2>", and "2>>".  The handle
      `2' refers to stderr.  If you redirect both stdout and stderr, you must
      use a different filename for each file.  Note that if you use the `+'
      flag or one of the automatically recognised DOS or OS/2 commands, the
      shell will process the redirection, not PAMAKE.

    - The Unix `make' only invokes the commands associated with inference
      rules (eg with ".c.obj:") either when no specific dependency appears in
      the makefile or when the specific dependency exactly matches what would
      have been inferred (e.g. "foo.obj: foo.c") and no command lines follow.
      PAMAKE extends the `exact match' to allow the inferred dependent name
      to be a substring of the actual dependent name.  This may make little
      sense without an example, but its effect is to allow inference rules and
      corresponding commands to be used even if the source file is in a
      different directory.  Here is the example:

          .c.obj:
                  cl /c $<

           MYSRC=c:\mysrc

           foo.exe: foo1.obj foo2.obj
                  link ...

           foo1.obj: $(MYSRC)\foo1.c

      The Unix make would execute the cl command for foo2 if foo2.c is in the
      current directory, but would not execute cl for foo1 even if foo1.c is
      in the mysrc directory.  PAMAKE will execute the cl command automatically
      for both.  Note: case is significant in determining whether a substring
      condition exists.

    - The $< $* $@ and $? macros are always evaluated before processing a
      command.  In Unix make the first two only apply to inference rules and
      the second two only to explicit dependency lists.  The $< evaluates to
      the complete `inferred' filename if an inference rule has been used.
      Otherwise (i.e. if an explicit command line was supplied or if no
      inference rule could be made) $< evaluates to the FIRST dependency file
      listed for this target.  $* on a command line always evaluates to the
      filename part of $< (i.e. less the extension).

    - The special macro $- indicates, when found on a command line, that the
      immediately following lines in the makefile are to be written to a
      temporary file (with macro expansion) immediately prior to executing the
      command.  This `local input file' must be terminated in the makefile by
      a line containing the character `<' in the first column.  The $- macro is
      expanded on the command line, and defaults to a value of `TEMP_LIF.TMP'
      (but can be redefined).  This macro expansion is used as the file name
      for the temporary file, so take care that it does not designate a file
      you need to retain.  If $- evaluates to a null string, the default file
      name TEMP_LIF.TMP is used for the file name but the macro expansion is
      left as null.  A typical command line would be `LIB @$-' which tells LIB
      that the filename TEMP_LIF.TMP contains the librarian commands.  The
      temporary file is deleted after the command has finished, and is not
      created if the -n switch has been given.  The string `\n' in a local
      input file line is converted into an extra newline.

    - A special macro `$\' has been added which evaluates to a backslash (`\')
      except in the VMS version, when it is undefined.  If you use this macro
      to separate a path and a filename in your makefiles, instead of
      hardcoding a backslash, it will be easier to use parts of the makefile
      under VMS, where the backslash is not required.  The reason we create
      this macro internally is that it is a little tricky to define it in
      a makefile (think about how you would do it, and remember the line
      continuation feature).

    - A special expansion of the macro `$*' is performed when the macro
      occurs in a dependency name.  The macro is expanded to the basename
      of the current target.  This allows makefiles of the form:

              OBJS= obj1.obj obj2.obj ...
              $(OBJS): \other\$*.c hdr.h
                      cl -Fo$@ $<

      In the above example, $* evaluates to `obj1' for the target `obj1.obj',
      and to `obj2' for the target `obj2.obj' etc.  When the command is
      actually performed, `$<' expands to `\other\obj1.c' etc.

    - A line starting (in column 1) with the string:  #include  is a signal to
      the input routine to attempt to open an `include' file.  The whole of
      the remainder of the input line is taken to be the file name, which
      should NOT be enclosed in double quote characters or angle brackets.
      PAMAKE does not search multiple directories for the file:  since the
      makefile specifies all such directories, we assume that at the very
      least you know where the include files are when you write the makefile.
      For convenience, PAMAKE does accept and expand any macros in the
      filename.  Include files may be nested to a depth of four levels.  The
      #include line may be placed anywhere in the input file except
      immediately following a line ending in `\'.  If the `#' does not start
      in column 1 it will be taken as a normal comment.  If you need to start
      a line with `#include' (for example in a local input file) the use of
      an escape (`\#include') will allow this.

    - Conditional processing of makefile lines is supported.  Special `comment'
      lines starting `#if', `#ifn', `#else' and `#endif' have the effect you
      would expect on the lines they enclose.  The syntax for the statement on
      `#if' and `#ifn' lines is exactly the same as a macro definition and
      currently you can only test macro values, and only for equality.  Note
      that a single equals sign is used as in the following example:

              #if M=s
              MODEL=small
              #endif

      The macro name on the left of the equality statement should NOT have
      a `$' in front of it.  This conditional processing takes place when
      the makefile is first read in, and a macro name on the left of the
      conditional takes its value at the time the conditional is processed.
      The right side of the conditional is macro-expanded before the test.
      Conditionals may be nested up to ten levels deep.

    - Conditional processing of command lines is supported.  Special command
      lines starting `%if', `%ifn', `%else' and `%endif' (following a tab)
      have the effect you would expect on the command lines lines they enclose.
      In addition a `%set' command line can be used to specify a macro
      definition which is made dynamically.  The syntax for the statement on
      `%if' and `%ifn' lines is exactly the same as a macro definition and
      currently you can only test macro values, and only for equality.  Note
      that a single equals sign is used as in the following example:

              %if @=foo.obj
              %set CFLAGS=$(SPECIALFLAGS)
              %else
              %set CFLAGS=$(DEFAULTFLAGS)
              %endif

      The macro name on the left of the equality statement should NOT have
      a `$' in front of it.  This conditional processing takes place when
      the command lines are executed, and a macro name on the left of the
      conditional takes its value at the time the conditional is processed.
      The right side of the conditional is macro-expanded before the test.
      Conditionals may be nested up to ten levels deep.  Note that each
      set of commands is processed separately and must be completed with
      the correct number of `%endif' statements, or the processing of the
      PAMAKE will be terminated.  Macros defined with the `%set' command
      stay defined for any further commands executed in the PAMAKE run.
      The special command `%exit' causes the make to be terminated
      immediately.  If a numeric value follows (e.g. `%exit 1') then it
      will be used as the exit code.  The special command `%stat filename'
      causes PAMAKE to update the file time of `filename' if it is already
      a target.

    - Special code has been inserted to handle the expansion of `$$' in a
      macro.  Many Unix `make' programs do not correctly handle file names
      including a `$' character when the needed `$$' is in a macro which
      gets expanded more than once.  The internal macro `$=$' which is
      normally used to expand the `$$' has been changed in PAMAKE to set the
      high bit of the replacement character, and the high bits are then
      stripped off before the result is actually used by PAMAKE.  If you have
      the PAMAKE source code, and if you never need the `$' in your makefiles,
      you can save a little time and memory by undefining the symbol DOLLAR
      in H.H.  The `$$' macro call will still work, but only if it is not
      expanded more than once.

    - The `-t' switch for `touch' has been disabled for VMS.  Touching a file
      on VMS apparently cannot be done without making RMS calls, and the
      concept is not really a useful one in a system which retains multiple
      versions of files.

`Make' overview
===============

For the benefit of users who are unfamiliar with make and do not have access
to Unix manuals, a very brief description of the PAMAKE features follows.
These features are common to most full `make' implementations.

    Command-line syntax:

      PAMAKE [-f filename] [-deinpqrst] [macro=value ...] [target(s) ...]

      Command-line switches can be combined in one string or entered as
      individual tokens in any order and intermixed with macro definitions.
      If the -f switch is given, the next following command line token will
      be taken as the file name.  If entered, target names must follow all the
      switches and macro definitions.

    Command-line switches:

      -f filename  Name of makefile (default is "makefile", "-" is stdin)
      -c           Confirm target timestamp after building
      -d           Print timestamps of files as they are analysed
      -e           Environment has priority over makefile macros
      -i           Ignore all exit status values
      -n           Execute no commands except $(MAKE)
      -p           Print all macros and targets
      -q           Question if target is up-to-date, exit(1) if not
      -r           Do not use the inbuilt rules
      -s           Make silently
      -t           Touch files instead of making them
      -v           Prints version information

    The MAKEFLAGS environment variable:

      The environment variable MAKEFLAGS can contain a string consisting of
      `-' followed by any of the flags `einqrst' which are processed as if
      they appeared on the command line.  An environment variable MAKEFLAGS
      containing the current settings of these flags is always passed on to
      commands executed by PAMAKE.

    Macros:

      On the command line, or in the makefile, you can use "str1=str2" to
      define a macro.  Macros are expanded with the syntax "$(str1)".  The
      parentheses may be omitted if str1 is a single character.  Case is
      significant.  If str1 is preceded by a `+' it is put in the DOS or OS/2
      environment as "STR1=str2", for the duration of the make execution only.
      Any existing environment variables at the start of the PAMAKE run are
      also available as macros.

    Macro redefinition and priority:

      A macro given on the command line cannot be redefined.  Macros defined
      in the makefile override environment variables with the same name unless
      the `-e' flag is given, but do not override the environment used for the
      commands executed by make unless they are preceded by a `+'.

    Macro value substitution:

      Macros in the makefile may also be expanded using the syntax:

            $(str1:subst1=subst2)

      The above expression specifies that the macro named `string1' should be
      expanded, and that in the expansion text all occurrences of `subst1'
      should be replaced by `subst2'.  If the equals sign and second
      substitution string are omitted then `subst1' is deleted.

    Target - Dependency - Commands specification:

      The basic syntax in the makefile is as follows:

           target:  dep1 dep2 dep3 ...
                   command1
                   command2
                   ...

      Command lines must start with a tab.  Target/Dependency lines may be
      continued by placing `\' at the end of the line.  Comments start with
      `#' and continue to the end of the line.  If `#' is required in a
      makefile line it must be escaped as `\#'.

      PAMAKE executes the commands to make the target if any of the dependent
      files have a later timestamp than the target, or if the target is not
      found.  If no targets are specified on the command line PAMAKE builds
      the first target encountered in the makefile.  The makefile is analysed
      recursively so that any dependencies of a target are also built in
      the correct sequence.

      In a line not beginning with a tab, the first `:' character delimits
      the target name.  A colon in a target name (e.g. a drive separator)
      can be escaped as `\:'.  Colons are permitted in dependancy names.

    Multiple command sequences:

      Multiple target:dependancy sets may be defined for a single target, but
      normally a target may only be associated with one list of commands.  If
      the target and dependancy names are separated with `::' instead of `:',
      however, each such line may be followed by a set of commands.  The
      first such set of commands is executed for which a dependancy name is
      later than the target.  This allows for alternatative methods of
      building a target depending on what files have changed.

    Special command prefixes:

      If a command is preceded by a special prefix character, special
      processing occurs.  Multiple prefix characters may be used.  The
      characters are as follows:

          +  execute this command through the command processor
          -  ignore error exit codes for this command
          @  execute this command silently

      If you need to use a command which starts with one of the special
      prefix characters, you can escape it with `\'.  This feature may be
      needed to run a VMS command file using the `@' command.

    Inference rules:

      The special target ".suff1.suff2" specifies how to make a file with
      suffix suff2 from a file with a matching basename and with the suffix
      suff1.

      As explained above, PAMAKE interprets `a matching basename' to mean that
      the target basename should be a substring of the dependency file
      basename.

      When the dependency file is in the same directory as the target, it is
      unnecessary to specify the dependency explicitly because PAMAKE will use
      the built-in or supplied inference rules and suffixes list (see below)
      to determine the correct command to execute.

    Special macros:

      $<     Expands to the main dependency filename which caused the current
             actions to be carried out (see above).

      $*     On a command line, expands to the basename, without the suffix,
             of $<.  In a dependency, expands to the basename, without the
             suffix, of the current target.  In the latter case, the
             expanded name will be different for each of multiple targets.

      $@     The current target

      $?     The list (whitespace-separated) of dependency names which are
             out-of-date with respect to the target

      $-     Defaults to expand to TEMP_LIF.TMP.  In a command line, indicates
             that the immediately following lines up to and not including the
             first line starting with `<' in column 1 are to be placed in a
             file which will have a name which is the expansion of the $-
             macro.  This file will be created immediately before executing the
             command in which the $- appears, and deleted afterwards.  If the
             $- macro evaluates to a null string, the default name
             TEMP_LIF.TMP is used for the file name instead of the macro
             expansion.

      $(MAKE)  If specified in a command, causes the command to be executed
             even if `-n' has been given.  This allows a `super-make' to call
             nested PAMAKE commands, passing the `-n' flag through MAKEFLAGS.
             $(MAKE) defaults to a value of `pamake'.

      $(HOME)  The current working drive and directory when the make started.

    Special targets:

      .PRECIOUS       Dependents of this target will not be removed when the
                      make is interrupted.

      .SILENT         Same as -s option

      .IGNORE         Same as -i option

      .DEFAULT        Used to specify commands to be used when a target is to
                      be built and no explicit commands or built-in rules can
                      be applied.

      .SUFFIXES       The dependants of .SUFFIXES are suffixes which are
                      applied in turn to the basename until one is found for
                      which an inference rule is present for which the created
                      file exists.  If dependants of .SUFFIXES are present
                      they are added to the built-in suffixes list; otherwise
                      the list is cleared.

    Built-in rules:

      PAMAKE has a number of built-in rules for creating object files from
      various different types of source file.  All are implemented using
      macros (eg the command for  .c.$O:  is $(CC) $(CFLAGS) $(CFILES) ).
      Unlike Unix make, the definitions of the macros such as O and CC are not
      built-in and must be defined in the makefile.  This allows for the
      variety of command and suffix names found outside the Unix environment.
      There is also a rule for code generation which can be used with the PANEL
      Plus C code genrator PANGENC.  The only built-in suffixes are .c, .asm
      and .pnl.

    Performance issues:

      The number of suffixes directly affects the performance of PAMAKE:
      since there is a built-in rule for `.pnl.c', each time a `.c' file is
      referenced PAMAKE must search for a `.pnl' file in case one is to be
      inferred.  To speed up PAMAKE, you can remove the .pnl suffix by
      specifying an empty `.SUFFIXES' and then one containing only .c (and
      .asm, if needed).  For example:

             .SUFFIXES:                 # clear suffixes list
             .SUFFIXES: .c .asm         # search only for these

      If you make this change, you will have to insert an explicit PANGENC
      command in the makefile every time it is needed to process a .pnl file.

Postscript
==========

As a final note, please remember that Roundhill is in the business of screen
management, not make utilites, and that PAMAKE is provided free of charge to
simplify your program development.  We shall attempt to fix any bugs in PAMAKE
which are reported, but it is not a `commercial product' and we do not plan to
enhance it to compete with full-featured make utilites already available on
the market.  Our modified source code is available in the same way as the
original public domain source.

Unix is a trademark of AT&T Bell Labs.


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