While you may not be familiar with it, you can find some form of m4 on. The m4 file extension associated with the m4, a general purpose macro processor designed by brian kernighan and dennis ritchie. If no files are specified or if is used in place of any files, input is read from the standard input. The name m4 also refers to the program which processes texts in this language. Gnu m4 is an implementation of the traditional unix macro processor. Html compressed 144k gzipped tar file with one web page per node. You can use it to process builtin macros or userdefined macros. Table 32 shows the files and subdirectories under the configuration directory of. As a macro processor m4 assisted in expansion of macros for code translation. The selinux reference policy relies heavily on the m4 macro processor. Gnu pic, sometimes called gpic, is an alternative that uses tpic specials see the readme file. The m4 command is a macro processor used as a preprocessor for c and other languages.
Gnu m4 gnu macro processor gnu project free software. Today m4 is used as a tool to generate configuration files, and is most famous as a generator of the sendmail. It operates as a character stream filter, recursively expanding macros as they are encountered. Mandatory or optional arguments to long options are mandatory or optional for short. M4 has roots in gpm general purpose macrogenerator.
M3 was in turn based on a macro processor implemented for 1. The macro processor library file type, file format description, and mac, windows, and linux programs listed on this page have been individually researched and verified by the fileinfo team. Bracket parameters with needed in surprising places, best to always do it integers dont need it. M4 is part of many unixbased operating systems, including linux.
M4 and the htm4l macros work in a very similar way. Html with one web page per node html compressed 116k gzipped characters entirely on one web page. In a program with macro activity, the macro processor can generate text that is placed on the input stack to be tokenized by the word scanner. Macro processor article about macro processor by the. The main purpose of m4 files is to set up configuration files.
For example, at the beginning of a program, you can define a symbolic name or symbolic constant as a particular string of characters. Solved m4 macro processor, use any character as delimiter. Configuring email manager and sendmail oracle help center. S as example, you can get the startup file in the folder below after installing the gecko sdk. Macros are either builtin or userdefined, and can take any number of arguments. The m4 macro processor provides builtin macros such as define. Its primary use has been as a front end for ratfor for those cases where parameterless macros are not adequately powerful. It is called a macro processor because it allows you to definemacros, which are brief abbreviations for longer constructs. This simple, awkbased macro processor is a surprisingly useful tool for manipulating text files the unix system provides several macro processors. This manual m4 is available in the following formats. Readers unfamiliar with the basic ideas of macro processing may wish to read some of the discussion there. You can buy printed copies of some manuals among other items from the free software foundation.
It is mostly svr4 compatible although it has some extensions for example, handling more than 9 positional parameters to macros. The c preprocessor, often known as cpp, is a macro processor that is used automatically by the c compiler to transform your program before compilation. Very recently ie last couple of days i added a few standard z88dk m4 macros to. Gnu macro processor introduction and preliminaries. Xpop was another attempt at a general macro processing language by mark halpern at ibm in the 1960s. The sendmail configuration is neither fun nor pretty. Gnu m4 also has builtin functions for including files, running shell commands, doing arithmetic, etc. Using the m4 macro processor to use the m4 macro processor, enter the following command. Besides just doing macro expansion, m4 has builtin functions for including named files, running shell commands, doing integer arithmetic, manipulating text in various ways. Its most often used to preprocess source code for a programming language. Using the m4 macro processor for fun and profit box.
The m4 macro processor has been in use on unix systems for a long time. Ive a main latex document with an associated \inputfile in it. Chapter 4 macro processors z a macro represents a commonly used group of statements in the source programming language. But its still worthwhile looking at some makefile s from reallife projects to see what people have done with make under the stress of providing deliverables. Understand the gnu assembler startup file of cortex m4. Pic interpreters include basic macro facilities, but the circuit macros and these examples extend the pic language using the more powerful m4 macro processor, which is available for unixlike systems and macs. A macro processor enables you to define and to use macros in your assembly programs. The m4 macro processor is a frontend processor for any programming language being used in the operating system environment the m4 macro processor is useful in many ways. When you define a macro, you provide text usually assembly code that you want to associate with a macro name. The m4 macro processor is one of the most advanced textual macroprocessing systems. Gnu m4 manual, online and for download in html, pdf, and other forms. You create a macro definition with the define command, one of about 20 builtin macros provided by m4.
Its main claim to fame is as a helper tool for the popular sendmail mailer configuration file. The directory structure that sendmail uses for example configuration code are designed to use a postv7 version m4 macro processor. The m4 utility is a macro processor that shall read one or more text files, process them according to their included macro statements, and write the results to standard output. The gnum4 macro processor is not limited to text and html editing.
Besides the straightforward replacement of one string of text by another, m4 enables you to perform integer arithmetic. It can prove very useful for programmers wishing to extend the features of cpp or to those wishing to have features equivalent to cpp with other languages. The assembler replaces the macro name with the text. It concludes by giving tips for reading the remainder of the manual. The makefile s shown throughout this book are industrial strength and quite suitable for adapting to your most advanced needs. They were designed for a unix macro processor using the m4 language. The m4 macro processor is an extension of a macro processor called m3 which was written by d. The example in this section shows you how the macro processor creates and resolves a macro variable. Ritchie bell laboratories murray hill, new jersey 07974 abstract m4 is a macro processor available on unix and gcos.
Our goal is to help you understand what a file with a. If the builtin macro divert n is used, all subsequent output is appended to a temporary file referred to as n. The m4 macro processor writes all redirected output to the temporary files in numerical order at the end of processing. It processes the files on the command line in the order given. The name means m, plus 4 more letters, or the word macro. Given this macro definition, the token n will be replaced by 100 wherever it appears in the file being processed. Xpedite2000 is a pmc pci mezzanine card form factor card that can process up to 2gbps of ipsec vpn or ssl bulk encryption with up to 20,000 rsa ops. Initially m4 was created as a preprocessor for fortran program code.
The output of the c preprocessor is then fed to the c compiler proper. A macro processor is a program which interprets commands named macros defined by the user. The macro processor replaces each macro instruction with the corresponding group of source language statements. This manual 24 february 2010 is for gnu m4 version 1. We strive for 100% accuracy and only publish information about file formats that we have. Then, when you want to include the macro text in your assembly program, you provide the name of the macro. It is an extension of an earlier macro processor m3, written by ritchie for an. Sendmails configuration file has an entire book devoted to it. This file is designed to be used with the p or prefixbuiltins commandline option. This helped to enhance program languages making them easier to read and help tailor them to an application. The m4 macro processor processes strings of letters and digits called tokens.
This file is generated by the combination of the m4 macro processor and dpic m4 file. If youre a c programmer, you know cpp, the c preprocessor, a simple macro processor. Exit status is 0 for success, 1 for failure, 63 for frozen file version mismatch, or whatever value was passed to the m4exit macro. The processed output is written to the standard output. Here, we discuss several example makefile s in detail. The m4 file stores preprocessor macro from the m4 software. The language was designed by brian kernighan and dennis ritchie for the original versions of unix.
Options the m4 utility shall conform to the base definitions volume of ieee std 1003. Gnu m4 gnu macro processor free software foundation last updated december 31, 2016. The m4 macro processor discards the output if you redirect the output to a temporary file other than 0 through 9. The shell contains powerful mechanisms for text manipulation. Extreme engineering, a design services and embedded products company has unveiled the xpedite2000 network security accelerator board, powered by the cavium networks nitrox security macro processor.