# Macro syntax

RPM has fully recursive spec file macros. Simple macros do straight text substitution. Parameterized macros include an options field, and perform argc/argv processing on white space separated tokens to the next newline. During macro expansion, both flags and arguments are available as macros which are deleted at the end of macro expansion. Macros can be used (almost) anywhere in a spec file, and, in particular, in "included file lists" (i.e. those read in using files -f <file>). In addition, macros can be nested, hiding the previous definition for the duration of the expansion of the macro which contains nested macros.

To define a macro use:

    	%define <name>[(opts)] <body>

All whitespace surrounding <body> is removed. Name may be composed of alphanumeric characters, and the character `_' and must be at least 3 characters in length. A macro without an (opts) field is "simple" in that only recursive macro expansion is performed. A parameterized macro contains an (opts) field. The opts (i.e. string between parantheses) is passed exactly as is to getopts(3) for argc/argv processing at the beginning of a macro invocation. While a parameterized macro is being expanded, the following shell-like macros are available:

    	%0	the name of the macro being invoked
    	%*	all arguments (unlike shell, not including any processed flags)
    	%#	the number of arguments
    	%{-f}	if present at invocation, the flag f itself
    	%{-f*}	if present at invocation, the argument to flag f
    	%1, %2	the arguments themselves (after getopt(3) processing)

At the end of invocation of a parameterized macro, the above macros are (at the moment, silently) discarded.

Within the body of a macro, there are several constructs that permit testing for the presence of optional parameters. The simplest construct is "%{-f}" which expands (literally) to "-f" if -f was mentioned when the macro was invoked. There are also provisions for including text if flag was present using "%{-f:X}". This macro expands to (the expansion of) X if the flag was present. The negative form, "%{!-f:Y}", expanding to (the expansion of) Y if -f was *not* present, is also supported.

In addition to the "%{...}" form, shell expansion can be performed using "%(shell command)". The expansion of "%(...)" is the output of (the expansion of) ... fed to /bin/sh. For example, "%(date +%y%m%d)" expands to the string "YYMMDD" (final newline is deleted). Note the 2nd % needed to escape the arguments to /bin/date. There is currently an 8K limit on the size that this macro can expand to.

There are several builtin macros (with reserved names) that are needed to perform useful operations. The current list is

    	%trace		toggle print of debugging information before/after
    			expansion
    	%dump		print the active (i.e. non-covered) macro table

    	%{echo:...}	print ... to stderr
    	%{warn:...}	print ... to stderr
    	%{error:...}	print ... to stderr and return BADSPEC

    	%define ...	define a macro
    	%undefine ...	undefine a macro
    	%global ...	define a macro whose body is available in global context

    	%{uncompress:...} expand ... to <file> and test to see if <file> is
    			compressed.  The expansion is
    				cat <file>		# if not compressed
    				gzip -dc <file>		# if gzip'ed
    				bzip2 -dc <file>	# if bzip'ed
    	%{expand:...}	like eval, expand ... to <body> and (re-)expand <body>

    	%{S:...}	expand ... to <source> file name
    	%{P:...}	expand ... to <patch> file name
    	%{F:...}	expand ... to <file> file name

Macros may also be automatically included from /usr/lib/rpm/macros. In addition, rpm itself defines numerous macros. To display the current set, add "%dump" to the beginning of any spec file, process with rpm, and examine the output from stderr.

Here is an example patch definition from /usr/lib/rpm/macros:

    	%patch(b:p:P:REz:) \
    	%define patch_file	%{P:%{-P:%{-P*}}%{!-P:%%PATCH0}} \
    	%define patch_suffix	%{!-z:%{-b:--suffix %{-b*}}}%{!-b:%{-z:--suffix %{-z*}}}%{!-z:%{!-b: }}%{-z:%{-b:%{error:Can't specify both -z(%{-z*}) and -b(%{-b*})}}} \
    		%{uncompress:%patch_file} | patch %{-p:-p%{-p*}} %patch_suffix %{-R} %{-E} \
    	...

The first line defines patch with its options. The body of patch is

    	%{uncompress:%patch_file} | patch %{-p:-p%{-p*}} %patch_suffix %{-R} %{-E}

The body contains 7 macros, which expand as follows

    	%{uncompress:...}	copy uncompressed patch to stdout
    	  %patch_file		... the name of the patch file
    	%{-p:...}		if "-p N" was present, (re-)generate "-pN" flag
    	  -p%{-p*}		... note patch-2.1 insists on contiguous "-pN"
    	%patch_suffix		override (default) ".orig" suffix if desired
    	%{-R}			supply -R (reversed) flag if desired
    	%{-E}			supply -E (delete empty?) flag if desired

There are two "private" helper macros:

    	%patch_file	the gory details of generating the patch file name
    	%patch_suffix	the gory details of overriding the (default) ".orig"

To use a macro, write:

    	%<name> ...

or

    	%{<name>}

The %{...} form allows you to place the expansion adjacent to other text. The %<name> form, if a parameterized macro, will do argc/argv processing of the rest of the line as described above. Normally you will likely want to invoke a parameterized macro by using the %<name> form so that parameters are expanded properly.

Example:

    	%define mymacro() (echo -n "My arg is %1" ; sleep %1 ; echo done.)

Usage:

    	%mymacro 5

This expands to:

    	(echo -n "My arg is 5" ; sleep 5 ; echo done.)

This will cause all occurances of 1 in the macro definition to be replaced by the first argument to the macro, but only if the macro is invoked as "%mymacro 5". Invoking as "%{mymacro} 5" will not work as desired in this case.

When the command line option "--define 'macroname value'" allows the user to specify the value that a macro should have during the build. Note lack of leading % for the macro name. We will try to support users who accidentally type the leading % but this should not be relied upon.

Evaluating a macro can be difficult outside of an rpm execution context. If you wish to see the expanded value of a macro, you may use the option

    	--eval '<macro expression>'

that will read rpm config files and print the macro expansion on stdout.

Note: This works only macros defined in rpm configuration files, not for macros defined in specfiles. You can use %{echo: %{your_macro_here}} if you wish to see the expansion of a macro defined in a spec file.

Starting in rpm 3.0, macros rather than rpmrc lines are used to configure rpm. In general, all the rpmrc configuration lines documented in "Maximum RPM" have been converted to macros, usually with a leading underscore, and the same name that was used in rpmrc files. In some cases, there is no leading underscore. Those macros existed in rpm-2.5.x and the underscore is omitted in order to preserve the meaning and usage of macros that are defined during spec file parsing.

Here's an example to illustrate configuration using macros:

       Old way:
    	In /etc/rpmrc and/or ~/.rpmrc you put
    		something:      some_value

       New way:
    	In /etc/rpm/macros and/or ~/.rpmmacros
    		%_something     some_value

Here are 2 common FAQ for experienced users of rpm:

      1) --rcfile works differently.
        Old way:	rpm --rcfile whatever
        New way:	rpm --rcfile /usr/lib/rpm/rpmrc:whatever

      2) topdir (and other rpmrc configurables) work differently.

        Old way:
    	~/.rpmrc contains
    		topdir:         whatever

        New way:
    	/usr/lib/rpm/rpmrc contains
    		macrofiles:     /usr/lib/rpm/macros: ... :~/.rpmmacros
    	~/.rpmmacros contains
    		%_topdir        whatever

Several macro definitions provided by the default rpm macro set have uses in packaging similar to the autoconf variables that are used in building packages:

        %_prefix		/usr
        %_exec_prefix	%{_prefix}
        %_bindir		%{_exec_prefix}/bin
        %_sbindir		%{_exec_prefix}/sbin
        %_libexecdir	%{_exec_prefix}/libexec
        %_datadir		%{_prefix}/share
        %_sysconfdir	%{_prefix}/etc
        %_sharedstatedir	%{_prefix}/com
        %_localstatedir	%{_prefix}/var
        %_libdir		%{_exec_prefix}/lib
        %_includedir	%{_prefix}/include
        %_oldincludedir	/usr/include
        %_infodir		%{_prefix}/info
        %_mandir		%{_prefix}/man