README.configure

   1
   2
   3                             Configuration
   4
   5          Last Mod Fri Apr 12 13:32:56 PDT 1991, by rich@sendai
   6
   7
   8 "Theory":
   9
  10 In this document, the word "host" refers to the environment in which
  11 this source will be compiled.  "host" and "host name" have nothing to
  12 do with the proper name of your host, like "ucbvax", "prep.ai.mit.edu"
  13 or "att.com".  Instead they refer to things like "sun4" and "dec3100".
  14
  15 Forget for a moment that this particular directory of source is the
  16 source for a development environment.  Instead, pretend that it is the
  17 source for a simpler, more mundane, application, say, a desk
  18 calculator.
  19
  20 Source that can be compiled in more than one environment, generally
  21 needs to be set up for each environment explicitly.
  22
  23 The word "target" refers to the environment produced by compiling this
  24 source and installing the resulting binaries.
  25
  26 For example, if configured for host sun4 and target sun4, this implies
  27 that we will compile on a sun4 to create a sun4 compilation
  28 environment.  If configured for host sun3 and target a29k, this
  29 implies that we will compile on a sun3 to create an a29k compilation
  30 environment.
  31
  32 Host sun3 only implies that the source will be compiled on a sun3.  In
  33 fact, it need not be actually compiled on a sun3.  If the appropriate
  34 native development tools, header files, libraries, and operating
  35 system support were available on a foobox, then source configured for
  36 a sun3 could be compiled on a foobox, resulting in a development
  37 environment for, using the previous example host+target pair, "a29k"
  38 on the foobox.  Similarly, if the appropriate cross development tools,
  39 header files, and libraries were available on a dec3100, then source
  40 configured for host sun3 could be cross compiled to create an a29k
  41 development environment intended to be run on a sun3.
  42
  43
  44 Usage:
  45
  46 Gdb's config has features not yet present in the uniform configuration
  47 scheme described here.  For this reason, configuration of gdb must
  48 currently be done separately from that of the rest of this package.
  49 This will be corrected soon.  For more information on the
  50 configuration of gdb, please refer to the documents in gdb.{your
  51 target} if it exists, otherwise gdb.
  52
  53 By "configures", I mean that links, Makefile, .gdbinit, and
  54 config.status are built.  Configuration is always done from the source
  55 directory.
  56
  57 * "./configure name" configures this directory, perhaps
  58   recursively, for a single host+target pair where the host and target
  59   are both "name".  If a previous configuration existed, it will be
  60   overwritten.
  61
  62 * "./configure +host=hostname targetname" configures this
  63   directory, perhaps recursively, for a single host+target pair where
  64   the host is hostname and target is targetname.  If a previous
  65   configuration existed, it will be overwritten.
  66
  67 * "./configure +forcesubdirs +host=hostname targetname" creates
  68   a subdirectories Host-hostname and
  69   Host-hostname/Target-targetname and configures
  70   Host-hostname/Target-targetname.  For now, makes should be
  71   done from Host-hostname/Target-targetname.  "./configure +f
  72   name" works as expected.  That is, it creates Host-name and
  73   Host-name/Target-name and configures the latter.
  74
  75
  76 Hacking configurations:
  77
  78 The configure scripts essentially do three things, create
  79 subdirectories if appropriate, build a Makefile, and create links to
  80 files, all based on and tailored to, a specific host+target pair.  The
  81 scripts also create a .gdbinit if appropriate but this is not
  82 tailored.
  83
  84 The Makefile is created by prepending some variable definitions to a
  85 Makefile template called Makefile.in and then inserting host and
  86 target specific Makefile fragments.  The variables are set based on
  87 the chosen host+target pair and build style, that is, if you use
  88 subdirectories or not.  The host and target specific Makefile
  89 may or may not exist.  If fragments
  90
  91 * Makefiles can be editted directly, but those changes will eventually
  92   be lost.  Changes intended to be permanent for a specific host
  93   should be made to the host specific Makefile fragment.  This should
  94   be in ./config/hmake-host if it exists.  Changes intended to be
  95   permanent for a specific target should be made to the target
  96   specific Makefile fragment.  This should be in ./config/tmake-target
  97   if it exists.  Changes intended to be permanent for the directory
  98   should be made in Makefile.in.  To propogate changes to any of
  99   these, either use "make Makefile" or re-configure from the source
 100   directory.
 101
 102 * configure can be editted directly, but those changes will eventually
 103   be lost.  Changes intended to be permanent for a specific directory
 104   should be made to configure.in.  Changes intended to be permanent
 105   for all configure scripts should be made to configure.template.
 106   Propogating changes to configure.in requires the presence of
 107   configure.template which normally resides in the uppermost directory
 108   you received.  To propogate changes to either configure.template or
 109   a configure.in, use "configure +template=absolutepathtothetemplate".
 110   This will configure the configure scripts themselves, recursively if
 111   appropriate.
 112
 113 * "configure -srcdir=foo" is not supported yet.  At the moment, things
 114   will probably be configured correctly only for leaf directories, and
 115   even they will not have paths to libraries set properly.