makefile format of MKS Make file	Miscellaneous Information
	DESCRIPTION SEE ALSO

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DESCRIPTION

This reference page offers a summary of the syntax of a makefile's contents, using a style similar to BNF (Backus Naur Form). Items enclosed in [ ] are optional, while items enclosed in { } can appear zero or more times.

makefile
  → { makefile-line }

makefile-line
  → macro-definition
  → target-definition
  → attribute-definition
  → conditional

A line is a possibly empty sequence of characters, terminated by a nonescaped newline character; that is, one not immediately preceded by a backslash (\). A line can be extended over several input lines by placing a \ at the end of each line to be continued.

A comment begins with a # and extends to the end of the line. In the following, an expression is defined as

expression
  → string
  → string == string
  → string != string

where string is defined as a literal sequence of characters, or the sequence of characters resulting from the expansion of a macro.

A conditional is defined as

conditional →
  .IF expression
   makefile
  { .ELSIF expression
   makefile
  }
  [ .ELSE
   makefile
  ]
  .END  

A rule-definition is defined as

rule-definition →
  targets [ attributes ] op [prerequisites] [ ; recipe ]
    recipe

targets →
  target { target }

A target may be a special-target.

Any number of attributes may follow a target in a rule-definition.

attribute
  → .IGNORE
  → .SILENT
  → .PRECIOUS
  → .LIBRARY
  → .PROLOG
  → .EPILOG
  → .SETDIR=path

An attribute-definition is like a rule-definition, except that a recipe is not allowed. An attribute-definition is given as

attribute-definition
  → attribute { attribute } : targets

The op defines the type of rule.

op
  → :
  → ::
  → :^
  → :!
  → :-
  → :|

The prerequisites are a list (possibly empty) of targets that must be brought up-to-date before making the current target. The prerequisites may optionally be followed by a semicolon (;) and a recipe.

A recipe normally follows; it consists of a number of lines, all starting with at least one tab character, or a group-recipe, which is written between brackets ([ ]).

recipe
  → { [+@-] line }
  → [[+@-]lines]

A special-target is a keyword that is given as a target in a rule-definition. The following special targets are allowed:

special-target
  → .BRACEEXPAND
  → .ERROR
  → .EXPORT
  → .GROUPEPILOG
  → .GROUPPROLOG
  → .IMPORT
  → .INCLUDE
  → .INCLUDEDIRS
  → .MAKEFILES
  → .NOAUTODEPEND
  → .REMOVE
  → .SOURCE
  → .SOURCE.suffix
  → .SUFFIXES
  → .POSIX

A macro-definition is recognized as a string followed by an = character. There are three forms of macros:

macro = string
  assign string to macro
macro := string
  expand macro definitions string, then assign
macro += string
  append string to end of macro

If string is empty, macro is assigned the null string (unless you use the += operator; in this case, the macros contents are not touched). White space on either side of the =, :=, or += is ignored.

Macros are expanded by $(macro) or ${macro}. If a macro name is a single letter, it can also be expanded by $n, where n is the name.

If the .BRACEEXPAND special target is set, make expands a token sequence (separated by white space) prepending a prefix string and appending a suffix string to each token:

string1{ token-list }string2

Future versions of MKS Make may not support this obsolescent feature.

A macro can also be modified as it is expanded. The syntax for this is

$(macro {:modifier})

where any number of modifiers can be supplied, separated by :.

modifier
  → b
  → d
  → f
  → l
  → s/string/new_string/
  → suffix_string=new_suffix_string
  → t"string"
  → u
  → ^"string"
  → +"string"

The :s modifier is a substitute operator; occurrences of the given pattern that are matched are replaced by the indicated value. The :t modifier tokenizes the macro string definition, placing the given string between each name in the indicated string. That string may contain the following escape sequences:

  \"  →  "
  \\  →  \
  \a  →  alert or <bel>
  \b  →  <backspace>
  \f  →  <form feed>
  \n  →  <newline>
  \r  →  <carriage return>
  \t  →  <tab>
  \v  →  <vertical tab>

The :u modifier maps all characters in the expansion to uppercase.

The :l modifier maps all characters in the expansion to lowercase.

The :^ modifier adds a prefix to all of the tokens in the expanded macro.

The :+ modifier adds a suffix to all of the tokens in the expanded macro.

A number of built-in macros are defined by MKS Make.

$@      full target name
$$@     dynamic expansion of $@
$%      full target name, or name of archive library
$$%     dynamic expansion of $%
$*      $@ without suffix; same as $(@:db)
$$*     dynamic expansion of $*
$>      library name for current target (library member)
$$>     dynamic expansion of $>
$?      all recently changed prerequisites
$<      in normal rules, those prerequisites prompting
        execution of current rule; in inference rules, the
        prerequisite of the current rule
$&      all prerequisites
$^      prerequisites in current rule

MKS Make also uses control-macros, whose value is either maintained by make, or used to control the corresponding attribute.

control-macros
  → DIRSEPSTR
  → .EPILOG
  → GROUPFLAGS
  → GROUPSHELL
  → GROUPSUFFIX
  → .IGNORE
  → INCDEPTH
  → MAKE
  → MAKECMD
  → MAKEDIR
  → MAKEFLAGS
  → MAKESTARTUP
  → MFLAGS
  → NULL
  → .PRECIOUS
  → .PROLOG
  → PWD
  → SHELL
  → SHELLFLAGS
  → SHELLMETAS
  → .SILENT

For example, the .SILENT macro is like the .SILENT attribute, except that using the macro assigns the .SILENT attribute to all targets.

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SEE ALSO

Commands:

make