Chapter 7. Variables defined by Bakefile
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Chapter 7. Variables defined by Bakefile

Table of Contents

Format independent variables
Changing Bakefile behaviour
Directories
Installation Directories
Recognizing Platform
Format features
Miscellaneous
Standard makefile variables
Format specific variables
autoconf
dmars, dmars_smake
msvs2005prj, msvs2008prj
msvs2003prj

Bakefile rulesets define lots of variables; this chapter provides brief summary of variables that are available for makefile writers.

Format independent variables

Changing Bakefile behaviour

These variables are meant to be changed using -D command line argument (see manual page for details).

Variable nameDescriptionDefault
OPTIONS_FILE If set, then user-configurable part of generated makefile (i.e. options list) is written into another file instead that the makefile will include. OPTIONS_FILE value must be relative to OUTPUT_FILE. (not set, empty)
WRITE_OPTIONS_FILE If OPTIONS_FILE is set and WRITE_OPTIONS_FILE is 1, then file OPTIONS_FILE is created. If 0, then it is not, but it is still included by the main makefile. This allows you to generate options file shared by lots of subproject makefiles and don't repeatedly generate it. 1

Variables for fine-tuning Bakefile's output (rarely needed):

Variable nameDescriptionDefault
VARS_DONT_ELIMINATE Bakefile normally eliminates all unused variables from the output. In some rare situations, it may not detect that a variable is used, in which case you can tell it to keep the variable by adding its name to this variable. So far this is only useful if the variables is used in makefile code included using fragment. (empty)
LIB_PAGESIZE Set this variable to a large power of two if your linker (on Windows) complains that page size is too small when building static library. 4096

Directories

Variable nameDescriptionDefault
SRCDIR

Directory to which names of source files are relative to. This value is relative to OUTPUT_FILE (the only exception is the autoconf format, which prefixes the value with $(srcdir) in order to allow out-of-tree compilation).

Note that the value of SRCDIR cannot be set manually; if you want to change it, you must use the set-srcdir command as early in your bakefile as possible. For example: 

<makefile>
  <set-srcdir>../..</set-srcdir>
  ..
</makefile>

The argument to set-srcdir must be a constant expression.

.
BUILDDIR Directory where object files and executables are built. This value is relative to OUTPUT_FILE. (depends on format)

Installation Directories

These are standard installation directories as used on Unix (most notably in Autoconf). They are used by install target if the backend supports it. They are defined on all platforms. You can change their values freely (unless you are using Autoconf backend).

Variable nameDescriptionDefault
PREFIXBase directory for installed files./usr/local on Unix
BINDIRDirectory where programs are installed.$(PREFIX)/bin on Unix
LIBDIRDirectory where libraries are installed.$(PREFIX)/lib on Unix
DLLDIRDirectory where DLLs are installed. $(PREFIX)/lib on Unix, $(PREFIX)/bin when targetting win32
INCLUDEDIRDirectory where C and C++ headers are installed.$(PREFIX)/include on Unix
DATADIRDirectory where data files are installed.$(PREFIX)/share on Unix

Recognizing Platform

All of these are variables defined to either 0 or 1, with the exception of autoconf format backend where they are options.

Variable nameDescription
PLATFORM_UNIXUNIX variant
PLATFORM_WIN3232bit Windows
PLATFORM_MSDOSMS-DOS
PLATFORM_MACMac OS X or Mac Classic
PLATFORM_MACOSXMac OS X
PLATFORM_OS2OS/2
PLATFORM_BEOSBeOS
PLATFORM_SYMBIANSymbian OS

Format features

Variable nameDescription
FORMAT_HAS_VARIABLES This boolean flag indicates whether the output format supports variables. If it does, then some space and time optimization are possible and long Bakefile variables that would otherwise be expanded into literals are left as variables in generated makefile/project.
FORMAT_SUPPORTS_CONDITIONS Whether the output format can handle conditions (i.e. variable values depending on conditions and conditionally built targets) at all. Most make-tools do, but e.g. MSVC project files can't do it. If set to 0, then the targets and variables are "flattened", i.e. expanded into multiple 'configurations' as in many IDEs.
FORMAT_SUPPORTS_CONFIGURATIONS Whether it is at least possible to have multiple configurations if conditions are not supported (such as in IDEs). Meaningless if FORMAT_SUPPORTS_CONDITIONS=1. If both FORMAT_SUPPORTS_CONDITIONS and FORMAT_SUPPORTS_CONFIGURATIONS are 0, then we're in deep trouble and we can only generate makefiles that are not configurable.
FORMAT_SUPPORTS_ACTIONS Whether the output format can handle actions at all. Most make-tools do, but IDE project files typically don't.
FORMAT_SUPPORTS_SUBPROJECTS Whether the output format can handle subprojects at all. Most make-tools do, but IDE project files typically don't.
FORMAT_NEEDS_OPTION_VALUES_FOR_CONDITIONS Whether the output format needs to have options that are used by conditions listed in the output file. This is true in majority of cases because the conditions take form such as "!if $(OPT) == value" and OPT must be defined, but there's one exception: autoconf. It decides on whether the condition is true or false in autoconf_inc.m4 and Makefile.in does not need the variables, so we can safely purge them and save some space.

Miscellaneous

Variable nameDescription
BAKEFILE_VERSION String with Bakefile version number. The version is formed from three numbers delimined by period. Read only.
OPTIONS Space-separation list of options defined in the makefiles. Note that the value of this variable changes during processing as new options are defined!  
INPUT_FILE Name of input file. The name is always absolute path. Read only.  
INPUT_FILE_ARG Same as INPUT_FILE, but the name is in exactly same form as it was passed on command line, it's not made absolute as in case of INPUT_FILE.  
OUTPUT_FILE Name of the file where generated native makefile will be written. Read only.  
FORMAT Format of makefile currently being generated, e.g. autoconf. Always constant expression.  
COMPILER Short identifier of used compiler (e.g. "bcc" or "vc6"). This variable is only defined for Windows compilers and is guaranteed to evaluate to constant expression.  
TOOLSET What kind of tools the makefile uses. Use this to determine what commands to put into command tags. Can be one of win32, unix. Always a constanst expression.  
EOL_STYLE Default line endings style for current format, one of unix, dos and mac.  
LF Line feed character (\n in C).  
TAB Tabelator character (\t in C).  
DOLLAR Dollar sign ($).  
SPACE Space character (" "). Note that SPACE is not evaluated and so you can't use it in places where constant expression is expected.  
DIRSEP Character used to separate directory components in paths on target platform (/ on Unix, \ on Windows).  

Standard makefile variables

Makefile-based formats (gnu, msvc etc.) define standard options CC, CXX, CFLAGS, CXXFLAGS, CPPFLAGS, LDFLAGS for specifying the compiler and its flags. Their default values are set to the default or typical compiler. If necessary, the defaults for FOO can be overriden by setting the DEFAULT_FOO (e.g. DEFAULT_CXX for the C++ compiler) variable to a constant value anywhere in user bakefiles.

Format specific variables

autoconf

Variable nameDescriptionDefault
AUTOCONF_MACROS_FILE

Where configure.in macros for setting options and conditional variables (mostly AC_SUBST calls) are written. This file must be included by your configure.in script. Set it to empty string to disable creation of this file (e.g. for subprojects of main project, see also OPTIONS_FILE ).

Note that the value of AUTOCONF_MACROS_FILE shouldn't be set manually; if you want to change it, use the autoconf-needs-macro command. For example: 

<makefile>
  <autoconf-needs-macro>AC_BAKEFILE_PYTHON</autoconf-needs-macro>
  ..
</makefile>

The argument to autoconf-needs-macro must be a constant expression. It can be repeated more than once.

autoconf_inc.m4

dmars, dmars_smake

Variable nameDescriptionDefault
DMARS_MEM_POOL_SIZE Specifies size of memory pool used by the dmc compiler. The default should be sufficient most of the time and only needs increasing if the compiler fails to compile source code with out of memory errors. 99

msvs2005prj, msvs2008prj

Variable nameDescriptionDefault
MSVS_PLATFORMS Comma-separated list of platforms to generate project configurations for. Can be set by the user using the -D command line argument. See MS VisualStudio 2005/2008 format documentation for details. win32
MSVS_PLATFORM This variable is not meant to be set by the user. It's an option created by the format itself. It's allowed values are values from MSVS_PLATFORMS variable set by the user. It can be used by the bakefiles to generate different project settings for different platform, in the same way user-added options are used.  
MSVS_PROJECT_FILE Unlike other variables in this section, this variable can optionally be set on targets to specify the location of .vcproj file created for them. The location is relative to OUTPUT_FILE. See an example: 
<exe id="hello_world">
  ...
  <!-- create subdirectory for projects if needed and put it there -->
  <set var="MSVS_PROJECT_FILE">examples/HelloWorld.vcproj</set>
</exe>
(derived from OUTPUT_FILE)

msvs2003prj

The MSVS_PLATFORM option is present in this format as well, but it is always set to win32. MSVS_PROJECT_FILE is fully supported.

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