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m4 (1)
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    NAME

    m4 - macro processor
     
    

    SYNOPSIS

    /usr/bin/m4 [-e] [-s] [-B int] [-H int] [-S int] 
        [-T int] [-Dname [=val]] ... [-U name] ... [file]...
    

    /usr/xpg4/bin/m4 [-e] [-s] [-B int] [-H int] [-S int] 
        [-T int] [-Dname [...=val]] [-U name] ... [file]...
    

     

    DESCRIPTION

    The m4 utility is a macro processor intended as a front end for C, assembler, and other languages. Each of the argument files is processed in order. If there are no files, or if a file is -, the standard input is read. The processed text is written on the standard output. Note: m4 cannot include more than nine nested files and writes a diagnostic message if that number is exceeded.  

    Macro Syntax

    Macro calls have the form:

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

    The open parenthesis character, (, must immediately follow the name of the macro. If the name of a defined macro is not followed by a (, it is deemed to be a call of that macro with no arguments. Potential macro names consist of alphanumeric characters and underscore (_), where the first character is not a digit.

    Leading unquoted blanks, TABs, and NEWLINEs are ignored while collecting arguments. Left and right single quotes are used to quote strings. The value of a quoted string is the string stripped of the quotes.  

    Macro Processing

    When a macro name is recognized, its arguments are collected by searching for a matching right parenthesis. If fewer arguments are supplied than are in the macro definition, the trailing arguments are taken to be NULL. Macro evaluation proceeds normally during the collection of the arguments, and any commas or right parentheses that 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.  

    OPTIONS

    The options and their effects are as follows:

    -Bint

    Changes the size of the push-back and argument collection buffers from the default of 4,096.

    -e

    Operates interactively. Interrupts are ignored and the output is unbuffered.

    -Hint

    Changes the size of the symbol table hash array from the default of 199. The size should be prime.

    -s

    Enables line sync output for the C preprocessor (#line ...)

    -Sint

    Changes the size of the call stack from the default of 100slots. Macros take three slots, and non-macro arguments take one.

    -Tint

    Changes the size of the token buffer from the default of 512bytes.

    To be effective, the above flags must appear before any file names and before any -D or -U flags:

    -D name[=val]

    Defines name to val or to NULL in val's absence.

    -Uname

    Undefines name.

     

    OPERANDS

    The following operand is supported:

    file

    A path name of a text file to be processed. If no file is given, or if it is -, the standard input is read.

     

    USAGE

    The m4 utility makes available the following built-in macros. These macros can be redefined, but once this is done the original meaning is lost. Their values are NULL unless otherwise stated.

    changequote

    Change quote symbols to the first and second arguments. The symbols can be up to five characters long. changequote without arguments restores the original values (that is, `').

    changecom

    Change left and right comment markers from the default # and NEWLINE. With no arguments, the comment mechanism is effectively disabled. With one argument, the left marker becomes the argument and the right marker becomes NEWLINE. With two arguments, both markers are affected. Comment markers can be up to five characters long.

    decr

    Returns the value of its argument decremented by 1.

    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; $# is replaced by the number of arguments; $* is replaced by a list of all the arguments separated by commas; $@ is like $*, but each argument is quoted (with the current quotes).

    defn

    Returns the quoted definition of its argument(s). It is useful for renaming macros, especially built-ins.

    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.

    divnum

    Returns the value of the current output stream.

    dnl

    Reads and discards characters up to and including the next NEWLINE.

    dumpdef

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

    errprint

    Prints its argument on the diagnostic output file.

    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.

    ifelse

    This macro 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.

    include

    Returns the contents of the file named in the argument.

    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.

    index

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

    len

    Returns the number of characters in its argument.

    m4exit

    This macro causes immediate exit from m4. Argument 1, if given, is the exit code; the default is 0.

    m4wrap

    Argument 1 is pushed back at final EOF. Example: m4wrap(`cleanup()')

    maketemp

    Fills in a string of "X" characters in its argument with the current process ID.

    popdef

    Removes current definition of its argument(s), exposing the previous one, if any.

    pushdef

    Like define, but saves any previous definition.

    shift

    Returns all but its first argument. The other arguments are quoted and pushed back with commas in between. The quoting nullifies the effect of the extra scan that is subsequently be performed.

    sinclude

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

    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.

    syscmd

    This macro executes the command given in the first argument. No value is returned.

    sysval

    This macro is the return code from the last call to syscmd.

    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.

    traceon

    This macro with no arguments, turns on tracing for all macros (including built-ins). Otherwise, turns on tracing for named macros.

    traceoff

    Turns off trace globally and for any macros specified.

    undefine

    Removes the definition of the macro named in its argument.

    undivert

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

     

    /usr/bin/m4

    eval

    Evaluates its argument as an arithmetic expression, using 32-bit signed-integer arithmetic. The following operators are supported: parentheses, unary -, unary +, !, ~, *, /, %, +, -, relationals, bitwise &, |, &&, and ||. Octal and hex numbers can be specified as in C. The second argument specifies the radix for the result; the default is 10. The third argument can be used to specify the minimum number of digits in the result.

     

    /usr/xpg4/bin/m4

    eval

    Evaluates its argument as an arithmetic expression, using 32-bit signed-integer arithmetic. The following operators are supported: parentheses, unary -, unary +, !, ~, *, /, %, +, -, <<, >>, relationals, bitwise &, |, &&, and ||. Precedence and associativity are as in C. Octal and hex numbers can also be specified as in C. The second argument specifies the radix for the result; the default is 10. The third argument can be used to specify the minimum number of digits in the result.

     

    EXAMPLES

    Example 1 Examples of m4 files

    If the file m4src contains the lines:

    The value of `VER' is "VER".
           ifdef(`VER', ``VER'' is defined to be VER., VER is not defined.)
           ifelse(VER, 1, ``VER'' is `VER'.)
           ifelse(VER, 2, ``VER'' is `VER'., ``VER'' is not 2.)
           end
    

    then the command:

    m4 m4src
    

    or the command:

    m4 -U VER m4src
    

    produces the output:

    The value of VER is "VER".
           VER is not defined.
    
           VER is not 2.
           end
    

    The command:

    m4 -D VER m4src
    

    produces the output:

    The value of VER is "".
           VER is defined to be .
    
           VER is not 2.
           end
    

    The command:

    m4 -D VER=1 m4src
    

    produces the output:

    The value of VER is "1".
          VER is defined to be 1.
          VER is 1.
          VER is not 2.
          end
    

    The command:

    m4 -D VER=2 m4src
    

    produces the output:

    The value of VER is "2".
           VER is defined to be 2.
    
           VER is 2.
           end
    

     

    ENVIRONMENT VARIABLES

    See environ(5) for descriptions of the following environment variables that affect the execution of m4: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.  

    EXIT STATUS

    The following exit values are returned:

    0

    Successful completion.

    >0

    An error occurred

    If the m4exit macro is used, the exit value can be specified by the input file.  

    ATTRIBUTES

    See attributes(5) for descriptions of the following attributes:  

    /usr/bin/m4

    ATTRIBUTE TYPEATTRIBUTE VALUE

    AvailabilitySUNWcsu

     

    /usr/xpg4/bin/m4

    ATTRIBUTE TYPEATTRIBUTE VALUE

    AvailabilitySUNWxcu4

    Interface Stability

     

    SEE ALSO

    as(1), attributes(5), environ(5), standards(5)


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    Macro Syntax
    Macro Processing
    OPTIONS
    OPERANDS
    USAGE
    /usr/bin/m4
    /usr/xpg4/bin/m4
    EXAMPLES
    ENVIRONMENT VARIABLES
    EXIT STATUS
    ATTRIBUTES
    /usr/bin/m4
    /usr/xpg4/bin/m4
    SEE ALSO


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