libguile/gen-scmconfig.c

   1
   2 /**********************************************************************
   3
   4   Description of Guile's public config header mechanics:
   5   -----------------------------------------------------
   6
   7   Guile has four core headers:
   8
   9     config.h: Guile's private automatically generated configuration
  10       header -- generated by configure.in and autoheader.  *NOT*
  11       installed during "make install" and so may not be referred to by
  12       any public headers.
  13
  14     libguile/_scm.h: Guile's private core header.  _scm.h is not
  15       installed.  It's only visible to the libguile sources
  16       themselves, and it includes config.h, the private config header.
  17       Among other things this file provides a place to make decisions
  18       based on the information gathered in config.h.
  19
  20     libguile/scmconfig.h: Guile's public automatically generated
  21       configuration header -- generated at build time by concatenating
  22       the contents of libguile/scmconfig.h.top with the output from
  23       libguile/gen-scmconfig.  gen-scmconfig bases its output on the
  24       information in the private config.h header, the contents of
  25       gen-scmconfig.h (which is created by configure.in from
  26       gen-scmconfig.h.in), and the information provided in this file,
  27       gen-scmconfig.c.
  28
  29     libguile/__scm.h: Guile's public core header.  This file is
  30       installed and publically visible.  It includes
  31       libguile/scmconfig.h, the public config header and provides a
  32       place to make decisions based on the information gathered in
  33       scmconfig.h to define things that other headers can depend on.
  34
  35    Notes and guidelines:
  36
  37    - use 1 and 0 for public #defines instead of "def and undef",
  38      i.e. use #define SCM_HAVE_FOO rather than just not defining
  39      SCM_HAVE_FOO whenever possible.  See GNU Coding Guidelines for
  40      rationale.  The only notable non-deprecated exceptions to this
  41      rule are GUILE_DEBUG and GUILE_DEBUG_FREELIST which do not follow
  42      this convention in order to retain backward compatibility.
  43
  44    - in the code below, be *VERY* careful not to use or rely on any
  45      runtime-dynamic information below.  For example, you cannot use
  46      sizeof (FOO), but must use static information like SIZEOF_BAR
  47      (from config.h) or SCM_SIZEOF_BAZ (from scmconfig.h).  This is
  48      because the gcc that is compiling gen-scmconfig.c and/or the
  49      machine that is running gen-scmconfig may not be the same
  50      compiler and/or hardware that will eventually be running Guile.
  51      (i.e. keep the cross-compilation case in mind).
  52
  53    - try to avoid adding names to the public namespace when possible.
  54      Note in the code below, that in a number of cases, we detect a
  55      feature and based on that, we decide whether or not to print
  56      anything at all.  This decreases the extraneous #defines and
  57      #ifdefery that we require in scmconfig.h
  58
  59    - try to avoid adding any duplicate definitions to config.h and
  60      scmconfig.h.  i.e. have just SCM_ENABLE_ELISP in scmconfig.h
  61      rather than ENABLE_ELISP in config.h and SCM_ENABLE_ELISP in
  62      scmconfig.h.
  63
  64    - in cases where you need to communicate information from
  65      configure.in to gen-scmconfig.c, don't add an AC_DEFINE unless
  66      you need it for other purposes.  Just add a suitable SCM_I_GSC_*
  67      variable to configure.in, set the value, AC_SUBST the value, and
  68      add an appropriate line to gen-scmconfig.h.in.  All gen-scmconfig
  69      related AC_SUBST vars should be prefixed with SCM_I_GSC_.
  70
  71    - make sure that anything that we explicitly typedef publically is
  72      prefixed with scm_t_.  i.e. we used to typedef long to ptrdiff_t
  73      if we didn't detect ptrdiff_t, but this has been changed so that
  74      we typedef scm_t_ptrdiff instead so that we won't conflict with
  75      any non-guile header definitions of the same type.  For types
  76      like intptr_t and uintptr_t which we just try to detect and don't
  77      actually define, it's fine not to have a corresponding scm_t_
  78      type.
  79
  80    - we now use SCM_SIZEOF_FOO != 0 rather than SCM_HAVE_FOO for any
  81      cases where the size might actually vary.  For types where the
  82      size is fixed, we use SCM_HAVE_FOO, i.e. you can see us define or
  83      not define SCM_HAVE_T_INT64 below when appropriate.
  84
  85    Rationales (not finished):
  86
  87      Why do we use a C program here rather than AC_OUTPUT_COMMANDS?
  88      --------------------------------------------------------------
  89
  90      The main reason is that there are some values we would need
  91      access to at AC_OUTPUT_COMMANDs that are determined by configure
  92      but are not available at AC_OUTPUT time.  The values are *only*
  93      available via config.h.  We use gen-scmconfig so we can see those
  94      values and make decisions based on their settings.
  95
  96      Why have gen-scmconfig.h.in?
  97      ----------------------------
  98
  99      Without that header, we could end up needing multiple aliases for
 100      public settings like SCM_ENABLE_ELISP.  We can't define
 101      SCM_ENABLE_ELISP in config.h since that header is private and any
 102      definition in scmconfig.h would conflict (#ifndef might be
 103      possible but runs the risk of conflicting directives), so a
 104      likely solution would be to AC_DEFINE([SCM_I_ENABLE_ELISP]), and
 105      then use SCM_I_ENABLE_ELISP in gen-scmconfig via config.h to
 106      determine whether or not to #define SCM_ENABLE_ELISP, but this
 107      leaves us with two #defined symbols for each public setting --
 108      better to just have one value (public or private) that all code
 109      uses.
 110
 111      Having this header means we can AC_SUBST a value like
 112      SCM_I_GSC_ENABLE_ELISP and then set it in here via AC_OUTPUT
 113      substitutions, and gen-scmconfig can use that definition to
 114      determine whether or not to #define SCM_ENABLE_ELISP when
 115      generating scmconfig.h, and we end up with nothing extraneous
 116      added to config.h.
 117
 118  **********************************************************************/
 119
 120 #if HAVE_CONFIG_H
 121 #  include <config.h>
 122 #endif
 123
 124 #include "gen-scmconfig.h"
 125
 126 #include <stdio.h>
 127 #include <string.h>
 128
 129 #define pf printf
 130
 131 int
 132 main (int argc, char *argv[])
 133 {
 134   pf ("/* This file is automatically generated --"
 135       " see configure.in for details */\n"
 136       "\n"
 137       "#ifndef SCM_SCMCONFIG_H\n"
 138       "#define SCM_SCMCONFIG_H\n");
 139
 140   /*** various important headers ***/
 141   pf ("\n");
 142   pf ("/* Important headers */\n");
 143   if (SCM_I_GSC_NEEDS_STDINT_H)
 144     pf ("#include <stdint.h>\n");
 145   if (SCM_I_GSC_NEEDS_INTTYPES_H)
 146     pf ("#include <inttypes.h>\n");
 147
 148 #ifdef HAVE_LIMITS_H
 149   pf ("#include <limits.h>\n");
 150 #else
 151   pf ("/* limits.h not available */\n");
 152 #endif
 153
 154 # ifdef TIME_WITH_SYS_TIME
 155   pf ("#include <sys/time.h>\n");
 156   pf ("#include <time.h>\n");
 157 # else
 158 #  ifdef HAVE_SYS_TIME_H
 159   pf ("#include <sys/time.h>\n");
 160 #  else
 161 #   ifdef HAVE_TIME_H
 162   pf ("#include <time.h>\n");
 163 #   endif
 164 #  endif
 165 # endif
 166
 167   pf("\n");
 168 #ifdef STDC_HEADERS
 169   pf ("#define SCM_HAVE_STDC_HEADERS 1 /* 0 or 1 */\n");
 170   pf ("#include <stdlib.h>\n");
 171 # if HAVE_SYS_TYPES_H
 172   pf ("#include <sys/types.h>\n");
 173 # endif
 174 # if HAVE_SYS_STDTYPES_H
 175   pf ("#include <sys/stdtypes.h>\n");
 176 # endif
 177   pf ("#include <stddef.h>\n");
 178 #else /* STDC_HEADERS */
 179   pf ("#define SCM_HAVE_STDC_HEADERS 0 /* 0 or 1 */");
 180 #endif /* def STDC_HEADERS */
 181
 182   pf("\n");
 183 #ifdef HAVE_SYS_SELECT_H
 184   pf ("#define SCM_HAVE_SYS_SELECT_H 1 /* 0 or 1 */\n");
 185 #else
 186   pf ("#define SCM_HAVE_SYS_SELECT_H 0 /* 0 or 1 */\n");
 187 #endif
 188
 189 #ifdef HAVE_FLOATINGPOINT_H
 190   pf ("#define SCM_HAVE_FLOATINGPOINT_H 1 /* 0 or 1 */\n");
 191 #else
 192   pf ("#define SCM_HAVE_FLOATINGPOINT_H 0 /* 0 or 1 */\n");
 193 #endif
 194
 195 #ifdef HAVE_IEEEFP_H
 196   pf ("#define SCM_HAVE_IEEEFP_H 1 /* 0 or 1 */\n");
 197 #else
 198   pf ("#define SCM_HAVE_IEEEFP_H 0 /* 0 or 1 */\n");
 199 #endif
 200
 201 #ifdef HAVE_NAN_H
 202   pf ("#define SCM_HAVE_NAN_H 1 /* 0 or 1 */\n");
 203 #else
 204   pf ("#define SCM_HAVE_NAN_H 0 /* 0 or 1 */\n");
 205 #endif
 206
 207 #ifdef HAVE_WINSOCK2_H
 208   pf ("#define SCM_HAVE_WINSOCK2_H 1 /* 0 or 1 */\n");
 209 #else
 210   pf ("#define SCM_HAVE_WINSOCK2_H 0 /* 0 or 1 */\n");
 211 #endif
 212
 213
 214   /*** GUILE_DEBUG (defined or undefined) ***/
 215   pf ("\n");
 216   pf ("/* Define to include various undocumented debugging functions. */\n");
 217   if (SCM_I_GSC_GUILE_DEBUG)
 218     pf ("#define GUILE_DEBUG 1 /* defined or undefined */\n");
 219   else
 220     pf ("/* #undef GUILE_DEBUG */\n");
 221
 222   /*** GUILE_DEBUG_FREELIST (deined or undefined) ***/
 223   pf ("\n");
 224   pf ("/* Define this to debug the free list (helps w/ GC bugs). */\n");
 225   if (SCM_I_GSC_GUILE_DEBUG_FREELIST)
 226     pf ("#define GUILE_DEBUG_FREELIST 1 /* defined or undefined */\n");
 227   else
 228     pf ("/* #undef GUILE_DEBUG_FREELIST */\n");
 229
 230   /*** SCM_ENABLE_DEPRECATED (0 or 1) ***/
 231   pf ("\n");
 232   pf ("/* Set to 1 if you want to enable deprecated features. */\n");
 233   pf ("/* (value will be 0 or 1). */\n");
 234   pf ("#define SCM_ENABLE_DEPRECATED %d\n", SCM_I_GSC_ENABLE_DEPRECATED);
 235
 236   /*** SCM_ENABLE_ELISP (0 or 1) ***/
 237   pf ("\n");
 238   pf ("/* Set to 1 to add Elisp support (in addition to Scheme). */\n");
 239   pf ("#define SCM_ENABLE_ELISP %d /* 0 or 1 */\n", SCM_I_GSC_ENABLE_ELISP);
 240
 241   /*** SCM_HAVE_ARRAYS (0 or 1) ***/
 242   pf ("\n");
 243   pf ("/* Set to 1 to add support for arrays and uniform arrays. */\n");
 244   pf ("#define SCM_HAVE_ARRAYS %d /* 0 or 1 */\n", SCM_I_GSC_HAVE_ARRAYS);
 245
 246   /*** SCM_STACK_GROWS_UP (0 or 1) ***/
 247   pf ("\n");
 248   pf ("/* Set to 1 if the stack grows up, 0 otherwise. */\n");
 249   pf ("#define SCM_STACK_GROWS_UP %d /* 0 or 1 */\n",
 250       SCM_I_GSC_STACK_GROWS_UP);
 251
 252   /*** SCM_C_INLINE (defined to appropriate string or undefined) ***/
 253   pf ("\n");
 254   pf ("/* C compiler's syntax for inline functions if any,\n"
 255       "   otherwise undefined. */\n");
 256   if (SCM_I_GSC_C_INLINE)
 257     pf ("#define SCM_C_INLINE %s\n", SCM_I_GSC_C_INLINE);
 258   else
 259     pf ("/* #undef SCM_C_INLINE */\n");
 260
 261   pf ("\n");
 262   pf ("/* Standard types. */\n");
 263
 264   pf ("/* These are always defined */\n");
 265   pf ("#define SCM_SIZEOF_CHAR %d\n", SIZEOF_CHAR);
 266   pf ("#define SCM_SIZEOF_UNSIGNED_CHAR %d\n", SIZEOF_UNSIGNED_CHAR);
 267   pf ("#define SCM_SIZEOF_SHORT %d\n", SIZEOF_SHORT);
 268   pf ("#define SCM_SIZEOF_UNSIGNED_SHORT %d\n", SIZEOF_UNSIGNED_SHORT);
 269   pf ("#define SCM_SIZEOF_LONG %d\n", SIZEOF_LONG);
 270   pf ("#define SCM_SIZEOF_UNSIGNED_LONG %d\n", SIZEOF_UNSIGNED_LONG);
 271   pf ("#define SCM_SIZEOF_INT %d\n", SIZEOF_INT);
 272   pf ("#define SCM_SIZEOF_UNSIGNED_INT %d\n", SIZEOF_UNSIGNED_INT);
 273
 274   pf ("\n");
 275   pf ("/* Size of (unsigned) long long or 0 if not available (scm_t_*64 may\n"
 276       "   be more likely to be what you want */\n");
 277   pf ("#define SCM_SIZEOF_LONG_LONG %d\n", SIZEOF_LONG_LONG);
 278   pf ("#define SCM_SIZEOF_UNSIGNED_LONG_LONG %d\n", SIZEOF_UNSIGNED_LONG_LONG);
 279
 280   pf ("\n");
 281   pf ("/* These are always defined. */\n");
 282   pf ("typedef %s scm_t_int8;\n", SCM_I_GSC_T_INT8);
 283   pf ("typedef %s scm_t_uint8;\n", SCM_I_GSC_T_UINT8);
 284   pf ("typedef %s scm_t_int16;\n", SCM_I_GSC_T_INT16);
 285   pf ("typedef %s scm_t_uint16;\n", SCM_I_GSC_T_UINT16);
 286   pf ("typedef %s scm_t_int32;\n", SCM_I_GSC_T_INT32);
 287   pf ("typedef %s scm_t_uint32;\n", SCM_I_GSC_T_UINT32);
 288
 289   pf ("\n");
 290   pf ("/* 64-bit integer -- if available SCM_HAVE_T_INT64 will be 1 and\n"
 291       "   scm_t_int64 will be a suitable type, otherwise SCM_HAVE_T_INT64\n"
 292       "   will be 0. */\n");
 293   if (SCM_I_GSC_T_INT64)
 294   {
 295     pf ("#define SCM_HAVE_T_INT64 1 /* 0 or 1 */\n");
 296     pf ("typedef %s scm_t_int64;\n", SCM_I_GSC_T_INT64);
 297   }
 298   else
 299     pf ("#define SCM_HAVE_T_INT64 0 /* 0 or 1 */\n");
 300
 301   pf ("\n");
 302   pf ("/* 64-bit unsigned integer -- if available SCM_HAVE_T_UINT64 will\n"
 303       "   be 1 and scm_t_uint64 will be a suitable type, otherwise\n"
 304       "   SCM_HAVE_T_UINT64 will be 0. */\n");
 305   if (SCM_I_GSC_T_UINT64)
 306   {
 307     pf ("#define SCM_HAVE_T_UINT64 1 /* 0 or 1 */\n");
 308     pf ("typedef %s scm_t_uint64;\n", SCM_I_GSC_T_UINT64);
 309   }
 310   else
 311     pf ("#define SCM_HAVE_T_UINT64 0 /* 0 or 1 */\n");
 312
 313   pf ("\n");
 314   pf ("/* scm_t_ptrdiff_t and size, always defined -- defined to long if\n"
 315       "   platform doesn't have ptrdiff_t. */\n");
 316   pf ("typedef %s scm_t_ptrdiff;\n", SCM_I_GSC_T_PTRDIFF);
 317   if (0 == strcmp ("long", SCM_I_GSC_T_PTRDIFF))
 318     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_LONG);
 319   else
 320     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_PTRDIFF_T);
 321
 322   pf ("\n");
 323   pf ("/* Size of intptr_t or 0 if not available */\n");
 324   pf ("#define SCM_SIZEOF_INTPTR_T %d\n", SIZEOF_INTPTR_T);
 325   pf ("/* Size of uintptr_t or 0 if not available */\n");
 326   pf ("#define SCM_SIZEOF_UINTPTR_T %d\n", SIZEOF_UINTPTR_T);
 327
 328   pf ("\n");
 329   pf ("/* same as POSIX \"struct timespec\" -- always defined */\n");
 330 #ifdef HAVE_STRUCT_TIMESPEC
 331   pf ("typedef struct timespec scm_t_timespec;\n");
 332 #else
 333   pf ("/* POSIX.4 structure for a time value.  This is like a `struct timeval'"
 334       "   but has nanoseconds instead of microseconds.  */\n");
 335   pf ("typedef struct\n"
 336       "{\n"
 337       "  long int tv_sec;               /* Seconds.  */\n"
 338       "  long int tv_nsec;              /* Nanoseconds.  */\n"
 339       "} scm_t_timespec;\n");
 340 #endif
 341
 342   pf ("\n");
 343   pf ("/*** Threading model (scmconfig.h support not finished) ***/\n");
 344
 345   pf ("/* Define to 1 if using pthread multithreading. */\n");
 346   pf ("#define SCM_USE_PTHREAD_THREADS %d /* 0 or 1 */\n",
 347       SCM_I_GSC_USE_PTHREAD_THREADS);
 348
 349   pf ("/* Define to 1 if using one-thread 'multi'threading. */\n");
 350   pf ("#define SCM_USE_NULL_THREADS %d /* 0 or 1 */\n",
 351       SCM_I_GSC_USE_NULL_THREADS);
 352
 353   pf ("/* FIXME: what is this used for now? */\n");
 354   pf ("#define SCM_USE_COOP_THREADS %d /* 0 or 1 */\n",
 355       SCM_I_GSC_USE_COOP_THREADS);
 356
 357 #if USE_DLL_IMPORT
 358   pf ("\n");
 359   pf ("/* Define some additional CPP macros on Win32 platforms. */\n");
 360   pf ("# define __REGEX_IMPORT__ 1\n");
 361   pf ("# define __CRYPT_IMPORT__ 1\n");
 362   pf ("# define __READLINE_IMPORT__ 1\n");
 363   pf ("# define QT_IMPORT 1\n");
 364 #endif
 365
 366   pf ("\n");
 367   pf ("#if SCM_ENABLE_DEPRECATED == 1\n"
 368       "# define USE_THREADS 1 /* always true now */\n"
 369       "# define GUILE_ISELECT 1 /* always true now */\n"
 370       "# define READER_EXTENSIONS 1 /* always true now */\n"
 371       "# define DEBUG_EXTENSIONS 1 /* always true now */\n"
 372       "# define DYNAMIC_LINKING 1 /* always true now */\n"
 373       "#endif\n");
 374   printf ("\n");
 375
 376   printf ("#endif\n");
 377
 378   return 0;
 379 }