M4(1)                   COMMAND REFERENCE                   M4(1)



NAME
     m4 - macro processor

SYNOPSIS
     M4 [ files ]

DESCRIPTION
     M4 is a macro processor intended as a front end for Ratfor,
     C, and other languages. Each of the argument files is
     processed in order; if there are no arguments, or if an
     argument is `-', the standard input is read.  The processed
     text is written on the standard output.

     Macro calls have the form

     name(arg1,arg2, . . . , argn)

     The `(' must immediately follow the name of the macro.  If a
     defined macro name is not followed by a `(', it is deemed to
     have no arguments.  Leading unquoted blanks, tabs, and
     newlines are ignored while collecting arguments. Potential
     macro names consist of alphabetic letters, digits, and
     underscore `_', where the first character is not a digit.

     Left and right single quotes (`') are used to quote strings.
     The value of a quoted string is the string stripped of the
     quotes.

     When a macro name is recognized, its arguments are collected
     by searching for a matching right parenthesis.  Macro
     evaluation proceeds normally during the collection of the
     arguments, and any commas or right parentheses which happen
     to turn up within the value of a nested call are as
     effective as those in the original input text.  After
     argument collection, the value of the macro is pushed back
     onto the input stream and rescanned.

     M4 makes available the following built-in macros.  They may
     be redefined, but once this is done the original meaning is
     lost.  Their values are null unless otherwise stated.

     define
         The second argument is installed as the value of the
         macro whose name is the first argument.  Each occurrence
         of $n in the replacement text, where n is a digit, is
         replaced by the n-th argument. Argument 0 is the name of
         the macro; missing arguments are replaced by the null
         string.

     undefine
         removes the definition of the macro named in its
         argument.



Printed 10/17/86                                                1

M4(1)                   COMMAND REFERENCE                   M4(1)



     ifdef
         If the first argument is defined, the value is the
         second argument, otherwise the third. If there is no
         third argument, the value is null.  The word unix is
         predefined on UTek versions of m4.

     changequote
         Change quote characters to the first and second
         arguments.  Changequote without arguments restores the
         original values (i.e., `').

     divert
         M4 maintains 10 output streams, numbered 0-9.  The final
         output is the concatenation of the streams in numerical
         order; initially stream 0 is the current stream. The
         divert macro changes the current output stream to its
         (digit-string) argument.  Output diverted to a stream
         other than 0 through 9 is discarded.

     undivert
         causes immediate output of text from diversions named as
         arguments, or all diversions if no argument.  Text may
         be undiverted into another diversion.  Undiverting
         discards the diverted text.

     divnum
         returns the value of the current output stream.

     dnl reads and discards characters up to and including the
         next newline.

     ifelse
         has three or more arguments.  If the first argument is
         the same string as the second, then the value is the
         third argument.  If not, and if there are more than four
         arguments, the process is repeated with arguments 4, 5,
         6 and 7.  Otherwise, the value is either the fourth
         string, or, if it is not present, null.

     incr
         returns the value of its argument incremented by 1.  The
         value of the argument is calculated by interpreting an
         initial digit-string as a decimal number.

     eval
         evaluates its argument as an arithmetic expression,
         using 32-bit arithmetic.  Operators include +, -, *, /,
         %, ^ (exponentiation); relationals; parentheses.

     len returns the number of characters in its argument.

     index



Printed 10/17/86                                                2

M4(1)                   COMMAND REFERENCE                   M4(1)



         returns the position in its first argument where the
         second argument begins (zero origin), or -1 if the
         second argument does not occur.

     substr
         returns a substring of its first argument.  The second
         argument is a zero origin number selecting the first
         character; the third argument indicates the length of
         the substring.  A missing third argument is taken to be
         large enough to extend to the end of the first string.

     translit
         transliterates the characters in its first argument from
         the set given by the second argument to the set given by
         the third.  No abbreviations are permitted.

     include
         returns the contents of the file named in the argument.

     sinclude
         is identical to include, except that it says nothing if
         the file is inaccessible.

     syscmd
         executes the UN*X command given in the first argument.
         No value is returned.

     maketemp
         fills in a string of XXXXX in its argument with the
         current process id.

     errprint
         prints its argument on the diagnostic output file.

     dumpdef
         prints current names and definitions, for the named
         items, or for all if no arguments are given.

SEE ALSO
     ratfor(1).















Printed 10/17/86                                                3

%%index%%
na:72,56;
sy:128,88;
de:216,2187;2547,2463;5154,1668;
se:6822,93;
%%index%%000000000099