Documentation/howto-build-sys.txt

   1 util-linux build system
   2 =======================
   3
   4  - the build system is non-recursive, individual subdirectories use
   5    Makemodule.am files. These files are merged together by automake
   6    into one global Makefile in the top-level directory
   7
   8  - all final build results (binaries, libtool scripts) are stored in top-level
   9    source directory
  10
  11  - all Makemodule.am files have to be designed as top-level makefiles, it
  12    means with full paths (e.g. foo_SOURCES = subdir/foo.c)
  13
  14  - always use '+=' operator for global variables (e.g. bin_PROGRAMS += foo)
  15
  16  - use libcommon.la (without path!) for lib/ stuff (e.g. foo_LDADD = libcommon.la)
  17
  18  - for libblkid, libuuid and libmount use lib<name>.la in _LDADD and
  19    -I$(ul_lib<name>_incdir) in _CFLAGS, for example
  20
  21         foo_LDADD = libmount.la
  22         foo_CFLAGS = -I$(ul_libmount_incdir)
  23
  24  - always use suffixes for hooks, for example
  25
  26         install-exec-hook-foo:
  27                 ln -sf foo foooo
  28
  29         INSTALL_EXEC_HOOKS += install-exec-hook-foo
  30
  31
  32  - all util-linux specific autoconf macros use UL_ prefix
  33
  34  - utils in Makefile.am files are enabled/disabled according to BUILD_<NAME>
  35    conditions (AM_CONDITIONAL), for example:
  36
  37         if BUILD_HWCLOCK
  38         ...
  39         endif
  40
  41  - "if BUILD_<NAME>" blocks are never nested within another "if BUILD_<NAME>",
  42    all dependencies have to be resolved in configure.ac (see UL_REQUIRES_BUILD())
  43
  44  - all BUILD_<NAME> in configure.am are always based on build_<name> variables,
  45    for example:
  46
  47         AM_CONDITIONAL([BUILD_HWCLOCK], test "x$build_hwclock" = xyes)
  48
  49    the $build_<name> should be available in whole configure script
  50
  51  - AC_ARG_ENABLE() status is always stored in $enable_<name> variable, possible
  52    setting:
  53
  54         "check" - util/feature is optional, if any subcomponent (function, lib,
  55                   ...) is missing a warning is printed and the util/feature is
  56                   disabled
  57
  58         "yes"   - util/feature is required, if any subcomponent (function, lib,
  59                   ...) is missing an error is printed and ./configure aborted
  60
  61         "no"    - the util/feature is unwanted
  62
  63    The default status is always defined by UL_DEFAULT_ENABLE() and it might be
  64    globally modified by $ul_default_estate (see AC_ARG_ENABLE([all-programs])).
  65
  66  - it's possible to disable all programs, but enable just one (or more)
  67    explicitly specified, for example:
  68
  69         ./configure --disable-all-programs --enable-hwclock
  70
  71  - some basic scenarios for the ./configure script are defined in the
  72    tools/config-gen.d/ directory. If you want to use these predefined scenarios
  73    then call
  74
  75         ./tools/config-gen [<scenario> ...]
  76
  77    for example
  78
  79         ./tools/config-gen all selinux
  80
  81    will build all utils with enabled selinux support. You can also define some
  82    CFLAGS, for example:
  83
  84         CFLAGS=$(rpm --eval '%optflags') ./tools/config-gen all
  85
  86    will use the default distro flags.
  87
  88    WARNING: config-gen is not designed for end-user or downstream distributions!
  89             It's for development purpose only. All end-users and downstream have
  90             to use standard ./configure script only.
  91
  92  - the tools/config-gen script is also used for build system regression tests,
  93    the test is not enabled by default, you have to use
  94
  95         tests/run.sh build-sys --force