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.

Defining a Macro

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. “-“ as opts disables all option processing, otherwise the opts (i.e. string between parentheses) are passed exactly as is to getopt(3) for argc/argv processing at the beginning of a macro invocation. “–” can be used to separate options from arguments. 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.

Writing a Macro

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)”.

Builtin Macros

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
	%getncpus	return the number of CPUs
	%getconfdir	expand to rpm "home" directory (typically /usr/lib/rpm)
	%dnl		discard to next line (without expanding)
	%verbose	expand to 1 if rpm is in verbose mode, 0 if not

	%{echo:...}	print ... to stdout
	%{warn:...}	print warning: ... to stderr
	%{error:...}	print error: ... to stderr and return an error
 
	%define ...	define a macro
	%undefine ...	undefine a macro
	%global ...	define a macro whose body is available in global context

	%{macrobody:...}	literal body of a macro

	%{basename:...}	basename(1) macro analogue
	%{dirname:...}	dirname(1) macro analogue
	%{exists:...}	test file existence, expands to 1/0
	%{suffix:...}	expand to suffix part of a file name
	%{url2path:...}	convert url to a local path
	%{getenv:...}	getenv(3) macro analogue
	%{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

	%{load:...}	load a macro file
	%{lua:...}	expand using the [embedded Lua interpreter](/rpm/manual/lua.html)
	%{expand:...}	like eval, expand ... to <body> and (re-)expand <body>
	%{expr:...}	evaluate an expression
	%{shescape:...}	single quote with escapes for use in shell
	%{shrink:...}	trim leading and trailing whitespace, reduce
			intermediate whitespace to a single space
	%{quote:...}	quote a parametric macro argument, needed to pass
			empty strings or strings with whitespace

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

Conditionally Expanded Macros

Sometimes it is useful to test whether a macro is defined or not. Syntax

%{?macro_name:value}
%{?!macro_name:value}

can be used for this purpose. %{?macro_name:value} is expanded to “value” if “macro_name” is defined, otherwise it is expanded to the empty string. %{?!macro_name:value} is the negative variant. It is expanded to “value” if “macro_name” not is defined. Otherwise it is expanded to the empty string.

Frequently used conditionally expanded macros are e.g. Define a macro if it is not defined:

%{?!with_python3: %global with_python3 1}

A macro that is expanded to 1 if “with_python3” is defined and 0 otherwise:

%{?with_python3:1}%{!?with_python3:0}

or shortly

0%{!?with_python3:1}

%”{?macro_name}” is a shortcut for “%{?macro_name:%macro_name}”.

For “macro_name” that is builtin macro conditionally expanded macros behave differently. In such a case both macro “%{?builtin_macro:value}” and its negative version “%{?!builtin_macro:value}” are expanded exactly like the macro without exclamation mark and question mark “%{builtin_macro:value}”. There is a special case among builtin macros:

%{?load:file}

it works like “%{load:file}” with the difference that the expansion does not emit an error if the file fails to load.

For more complex tests it is possible to use conditionals like %if, %ifarch or %ifos. But the conditionals are not macros thus they are not described here. For more information please refer to spec manual.

Example of a Macro

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"

Using a Macro

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 occurrences 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.

Shell Expansion

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.

Expression Expansion

Expression expansion can be performed using “%[expression]”. An expression consists of terms that can be combined using operators. Rpm supports three kinds of terms, numbers made up from digits, strings enclosed in double quotes (eg “somestring”) and versions enclosed in double quotes preceded by v (eg v”3:1.2-1”). Rpm will expand macros when evaluating terms.

You can use the standard operators to combine terms: logical operators &&, ||, !, relational operators !=, ==, <, > , <=, >=, arithmetic operators +, -, /, *, the ternary operator ? :, and parentheses. For example, “%[ 3 + 4 * (1 + %two) ]” will expand to “15” if “%two” expands to “2”. Version terms are compared using rpm version ([epoch:]version[-release]) comparison algorithm, rather than regular string comparison.

Note that the “%[expression]” expansion is different to the “%{expr:expression}” macro. With the latter, the macros in the expression are expanded first and then the expression is evaluated (without re-expanding the terms). Thus

	rpm --define 'foo 1 + 2' --eval '%{expr:%foo}'

will print “3”. Using ‘%[%foo]’ instead will result in the error that “1 + 2” is not a number.

Doing the macro expansion when evaluating the terms has two advantages. First, it allows rpm to do correct short-circuit processing when evaluation logical operators. Second, the expansion result does not influence the expression parsing, e.g. ‘%[“%file”] will even work if the “%file” macro expands to a string that contains a double quote.

Command Line Options

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.

Configuration using Macros

Most rpm configuration is done via macros. There are numerous places from which macros are read, in recent rpm versions the macro path can be seen with rpm --showrc|grep "^Macro path". If there are multiple definitions of the same macro, the last one wins. User-level configuration goes to ~/.rpmmacros which is always the last one in the path.

The macro file syntax is simply:

%<name>		 <body>

…where is a legal macro name and <body> is the body of the macro. Multiline macros can be defined by shell-like line continuation, ie `\` at end of line.

Note that the macro file syntax is strictly declarative, no conditionals are supported (except of course in the macro body) and no macros are expanded during macro file read.

Macro Analogues of Autoconf Variables

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	/etc
    %_sharedstatedir	%{_prefix}/com
    %_localstatedir	%{_prefix}/var
    %_libdir		%{_exec_prefix}/lib
    %_includedir	%{_prefix}/include
    %_oldincludedir	/usr/include
    %_infodir		%{_datadir}/info
    %_mandir		%{_datadir}/man