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 #ifdef HAVE_CONFIG_H
 121 #  include <config.h>
 122 #endif
 123
 124 #include <libguile/gen-scmconfig.h>
 125
 126 #include <stdio.h>
 127 #include <string.h>
 128 #include <uniconv.h>
 129
 130 #define pf printf
 131
 132 int
 133 main (int argc, char *argv[])
 134 {
 135   pf ("/* This file is automatically generated --"
 136       " see configure.in for details */\n"
 137       "\n"
 138       "#ifndef SCM_SCMCONFIG_H\n"
 139       "#define SCM_SCMCONFIG_H\n");
 140
 141   /*** various important headers ***/
 142   pf ("\n");
 143   pf ("/* Important headers */\n");
 144   if (SCM_I_GSC_NEEDS_STDINT_H)
 145     pf ("#include <stdint.h>\n");
 146   if (SCM_I_GSC_NEEDS_INTTYPES_H)
 147     pf ("#include <inttypes.h>\n");
 148
 149 #ifdef HAVE_LIMITS_H
 150   pf ("#include <limits.h>\n");
 151 #else
 152   pf ("/* limits.h not available */\n");
 153 #endif
 154
 155 # ifdef TIME_WITH_SYS_TIME
 156   pf ("#include <sys/time.h>\n");
 157   pf ("#include <time.h>\n");
 158 # else
 159 #  ifdef HAVE_SYS_TIME_H
 160   pf ("#include <sys/time.h>\n");
 161 #  else
 162 #   ifdef HAVE_TIME_H
 163   pf ("#include <time.h>\n");
 164 #   endif
 165 #  endif
 166 # endif
 167
 168   pf("\n");
 169 #ifdef STDC_HEADERS
 170   pf ("#define SCM_HAVE_STDC_HEADERS 1 /* 0 or 1 */\n");
 171   pf ("#include <stdlib.h>\n");
 172 # ifdef HAVE_SYS_TYPES_H
 173   pf ("#include <sys/types.h>\n");
 174 # endif
 175 # ifdef HAVE_SYS_STDTYPES_H
 176   pf ("#include <sys/stdtypes.h>\n");
 177 # endif
 178   pf ("#include <stddef.h>\n");
 179 #else /* STDC_HEADERS */
 180   pf ("#define SCM_HAVE_STDC_HEADERS 0 /* 0 or 1 */");
 181 #endif /* def STDC_HEADERS */
 182
 183   pf("\n");
 184 #ifdef HAVE_SYS_SELECT_H
 185   pf ("#define SCM_HAVE_SYS_SELECT_H 1 /* 0 or 1 */\n");
 186 #else
 187   pf ("#define SCM_HAVE_SYS_SELECT_H 0 /* 0 or 1 */\n");
 188 #endif
 189
 190 #ifdef HAVE_FLOATINGPOINT_H
 191   pf ("#define SCM_HAVE_FLOATINGPOINT_H 1 /* 0 or 1 */\n");
 192 #else
 193   pf ("#define SCM_HAVE_FLOATINGPOINT_H 0 /* 0 or 1 */\n");
 194 #endif
 195
 196 #ifdef HAVE_IEEEFP_H
 197   pf ("#define SCM_HAVE_IEEEFP_H 1 /* 0 or 1 */\n");
 198 #else
 199   pf ("#define SCM_HAVE_IEEEFP_H 0 /* 0 or 1 */\n");
 200 #endif
 201
 202 #ifdef HAVE_NAN_H
 203   pf ("#define SCM_HAVE_NAN_H 1 /* 0 or 1 */\n");
 204 #else
 205   pf ("#define SCM_HAVE_NAN_H 0 /* 0 or 1 */\n");
 206 #endif
 207
 208 #ifdef HAVE_WINSOCK2_H
 209   pf ("#define SCM_HAVE_WINSOCK2_H 1 /* 0 or 1 */\n");
 210 #else
 211   pf ("#define SCM_HAVE_WINSOCK2_H 0 /* 0 or 1 */\n");
 212 #endif
 213
 214
 215   /*** GUILE_DEBUG (defined or undefined) ***/
 216   pf ("\n");
 217   pf ("/* Define to include various undocumented debugging functions. */\n");
 218   if (SCM_I_GSC_GUILE_DEBUG)
 219     pf ("#define GUILE_DEBUG 1 /* defined or undefined */\n");
 220   else
 221     pf ("/* #undef GUILE_DEBUG */\n");
 222
 223   /*** SCM_ENABLE_DISCOURAGED (0 or 1) ***/
 224   pf ("\n");
 225   pf ("/* Set to 1 if you want to enable discouraged features. */\n");
 226   pf ("/* (value will be 0 or 1). */\n");
 227   pf ("#define SCM_ENABLE_DISCOURAGED %d\n", SCM_I_GSC_ENABLE_DISCOURAGED);
 228
 229   /*** SCM_ENABLE_DEPRECATED (0 or 1) ***/
 230   pf ("\n");
 231   pf ("/* Set to 1 if you want to enable deprecated features. */\n");
 232   pf ("/* (value will be 0 or 1). */\n");
 233   pf ("#define SCM_ENABLE_DEPRECATED %d\n", SCM_I_GSC_ENABLE_DEPRECATED);
 234
 235   /*** SCM_ENABLE_ELISP (0 or 1) ***/
 236   pf ("\n");
 237   pf ("/* Set to 1 to add Elisp support (in addition to Scheme). */\n");
 238   pf ("#define SCM_ENABLE_ELISP %d /* 0 or 1 */\n", SCM_I_GSC_ENABLE_ELISP);
 239
 240   /*** SCM_STACK_GROWS_UP (0 or 1) ***/
 241   pf ("\n");
 242   pf ("/* Set to 1 if the stack grows up, 0 otherwise. */\n");
 243   pf ("#define SCM_STACK_GROWS_UP %d /* 0 or 1 */\n",
 244       SCM_I_GSC_STACK_GROWS_UP);
 245
 246   /*** SCM_C_INLINE (defined to appropriate string or undefined) ***/
 247   pf ("\n");
 248   pf ("/* C compiler's syntax for inline functions if any,\n"
 249       "   otherwise undefined. */\n");
 250   if (SCM_I_GSC_C_INLINE)
 251     pf ("#define SCM_C_INLINE %s\n", SCM_I_GSC_C_INLINE);
 252   else
 253     pf ("/* #undef SCM_C_INLINE */\n");
 254
 255   pf ("\n");
 256   pf ("/* Standard types. */\n");
 257
 258   pf ("/* These are always defined */\n");
 259   pf ("#define SCM_SIZEOF_CHAR %d\n", SIZEOF_CHAR);
 260   pf ("#define SCM_SIZEOF_UNSIGNED_CHAR %d\n", SIZEOF_UNSIGNED_CHAR);
 261   pf ("#define SCM_SIZEOF_SHORT %d\n", SIZEOF_SHORT);
 262   pf ("#define SCM_SIZEOF_UNSIGNED_SHORT %d\n", SIZEOF_UNSIGNED_SHORT);
 263   pf ("#define SCM_SIZEOF_LONG %d\n", SIZEOF_LONG);
 264   pf ("#define SCM_SIZEOF_UNSIGNED_LONG %d\n", SIZEOF_UNSIGNED_LONG);
 265   pf ("#define SCM_SIZEOF_INT %d\n", SIZEOF_INT);
 266   pf ("#define SCM_SIZEOF_UNSIGNED_INT %d\n", SIZEOF_UNSIGNED_INT);
 267   pf ("#define SCM_SIZEOF_SIZE_T %d\n", SIZEOF_SIZE_T);
 268
 269   pf ("\n");
 270   pf ("/* Size of (unsigned) long long or 0 if not available (scm_t_*64 may\n"
 271       "   be more likely to be what you want */\n");
 272   pf ("#define SCM_SIZEOF_LONG_LONG %d\n", SIZEOF_LONG_LONG);
 273   pf ("#define SCM_SIZEOF_UNSIGNED_LONG_LONG %d\n", SIZEOF_UNSIGNED_LONG_LONG);
 274
 275   pf ("\n");
 276   pf ("/* These are always defined. */\n");
 277   pf ("typedef %s scm_t_int8;\n", SCM_I_GSC_T_INT8);
 278   pf ("typedef %s scm_t_uint8;\n", SCM_I_GSC_T_UINT8);
 279   pf ("typedef %s scm_t_int16;\n", SCM_I_GSC_T_INT16);
 280   pf ("typedef %s scm_t_uint16;\n", SCM_I_GSC_T_UINT16);
 281   pf ("typedef %s scm_t_int32;\n", SCM_I_GSC_T_INT32);
 282   pf ("typedef %s scm_t_uint32;\n", SCM_I_GSC_T_UINT32);
 283   pf ("typedef %s scm_t_intmax;\n", SCM_I_GSC_T_INTMAX);
 284   pf ("typedef %s scm_t_uintmax;\n", SCM_I_GSC_T_UINTMAX);
 285   pf ("typedef %s scm_t_intptr;\n", SCM_I_GSC_T_INTPTR);
 286   pf ("typedef %s scm_t_uintptr;\n", SCM_I_GSC_T_UINTPTR);
 287
 288   if (0 == strcmp ("intmax_t", SCM_I_GSC_T_INTMAX))
 289     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF_INTMAX_T);
 290   else if (0 == strcmp ("long long", SCM_I_GSC_T_INTMAX))
 291     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF_LONG_LONG);
 292   else if (0 == strcmp ("__int64", SCM_I_GSC_T_INTMAX))
 293     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF___INT64);
 294   else
 295     return 1;
 296
 297   pf ("\n");
 298   pf ("/* 64-bit integer -- if available SCM_HAVE_T_INT64 will be 1 and\n"
 299       "   scm_t_int64 will be a suitable type, otherwise SCM_HAVE_T_INT64\n"
 300       "   will be 0. */\n");
 301   if (SCM_I_GSC_T_INT64)
 302   {
 303     pf ("#define SCM_HAVE_T_INT64 1 /* 0 or 1 */\n");
 304     pf ("typedef %s scm_t_int64;\n", SCM_I_GSC_T_INT64);
 305   }
 306   else
 307     pf ("#define SCM_HAVE_T_INT64 0 /* 0 or 1 */\n");
 308
 309   pf ("\n");
 310   pf ("/* 64-bit unsigned integer -- if available SCM_HAVE_T_UINT64 will\n"
 311       "   be 1 and scm_t_uint64 will be a suitable type, otherwise\n"
 312       "   SCM_HAVE_T_UINT64 will be 0. */\n");
 313   if (SCM_I_GSC_T_UINT64)
 314   {
 315     pf ("#define SCM_HAVE_T_UINT64 1 /* 0 or 1 */\n");
 316     pf ("typedef %s scm_t_uint64;\n", SCM_I_GSC_T_UINT64);
 317   }
 318   else
 319     pf ("#define SCM_HAVE_T_UINT64 0 /* 0 or 1 */\n");
 320
 321   pf ("\n");
 322   pf ("/* scm_t_ptrdiff_t and size, always defined -- defined to long if\n"
 323       "   platform doesn't have ptrdiff_t. */\n");
 324   pf ("typedef %s scm_t_ptrdiff;\n", SCM_I_GSC_T_PTRDIFF);
 325   if (0 == strcmp ("long", SCM_I_GSC_T_PTRDIFF))
 326     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_LONG);
 327   else
 328     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_PTRDIFF_T);
 329
 330   pf ("\n");
 331   pf ("/* Size of intptr_t or 0 if not available */\n");
 332   pf ("#define SCM_SIZEOF_INTPTR_T %d\n", SIZEOF_INTPTR_T);
 333   pf ("/* Size of uintptr_t or 0 if not available */\n");
 334   pf ("#define SCM_SIZEOF_UINTPTR_T %d\n", SIZEOF_UINTPTR_T);
 335
 336   pf ("\n");
 337   pf ("/* same as POSIX \"struct timespec\" -- always defined */\n");
 338 #ifdef HAVE_STRUCT_TIMESPEC
 339   pf ("typedef struct timespec scm_t_timespec;\n");
 340 #else
 341   pf ("/* POSIX.4 structure for a time value.  This is like a `struct timeval'"
 342       "   but has nanoseconds instead of microseconds.  */\n");
 343   pf ("typedef struct\n"
 344       "{\n"
 345       "  long int tv_sec;               /* Seconds.  */\n"
 346       "  long int tv_nsec;              /* Nanoseconds.  */\n"
 347       "} scm_t_timespec;\n");
 348 #endif
 349
 350   pf ("\n");
 351   pf ("/*** Threading model (scmconfig.h support not finished) ***/\n");
 352
 353   pf ("/* Define to 1 if using pthread multithreading. */\n");
 354   pf ("#define SCM_USE_PTHREAD_THREADS %d /* 0 or 1 */\n",
 355       SCM_I_GSC_USE_PTHREAD_THREADS);
 356
 357   pf ("/* Define to 1 if using one-thread 'multi'threading. */\n");
 358   pf ("#define SCM_USE_NULL_THREADS %d /* 0 or 1 */\n",
 359       SCM_I_GSC_USE_NULL_THREADS);
 360
 361   pf ("/* Define to 1 if need braces around PTHREAD_ONCE_INIT (for Solaris). */\n");
 362   pf ("#define SCM_NEED_BRACES_ON_PTHREAD_ONCE_INIT %d /* 0 or 1 */\n",
 363       SCM_I_GSC_NEED_BRACES_ON_PTHREAD_ONCE_INIT);
 364
 365   pf ("/* Define to 1 if need braces around PTHREAD_MUTEX_INITIALIZER\n"
 366       "   (for IRIX with GCC)  */\n");
 367   pf ("#define SCM_NEED_BRACES_ON_PTHREAD_MUTEX_INITIALIZER %d /* 0 or 1 */\n",
 368       SCM_I_GSC_NEED_BRACES_ON_PTHREAD_MUTEX_INITIALIZER);
 369
 370   pf ("\n\n/*** File system access ***/\n");
 371
 372   pf ("/* Define to 1 if `struct dirent64' is available.  */\n");
 373   pf ("#define SCM_HAVE_STRUCT_DIRENT64 %d /* 0 or 1 */\n",
 374       SCM_I_GSC_HAVE_STRUCT_DIRENT64);
 375
 376   pf ("/* Define to 1 if `readdir64_r ()' is available.  */\n");
 377 #ifdef HAVE_READDIR64_R
 378   pf ("#define SCM_HAVE_READDIR64_R 1 /* 0 or 1 */\n");
 379 #else
 380   pf ("#define SCM_HAVE_READDIR64_R 0 /* 0 or 1 */\n");
 381 #endif
 382
 383   /* Arrange so that we have a file offset type that reflects the one
 384      used when compiling Guile, regardless of what the application's
 385      `_FILE_OFFSET_BITS' says.  See
 386      http://lists.gnu.org/archive/html/bug-guile/2009-06/msg00018.html
 387      for the original bug report.
 388
 389      Note that we can't define `scm_t_off' in terms of `off_t' or
 390      `off64_t' because they may or may not be available depending on
 391      how the application that uses Guile is compiled.  */
 392
 393 #if defined GUILE_USE_64_CALLS && defined HAVE_STAT64
 394   pf ("typedef scm_t_int64 scm_t_off;\n");
 395 #elif SIZEOF_OFF_T == SIZEOF_INT
 396   pf ("typedef int scm_t_off;\n");
 397 #else
 398   pf ("typedef long int scm_t_off;\n");
 399 #endif
 400
 401   pf ("/* Define to 1 if the compiler supports the "
 402       "`__thread' storage class.  */\n");
 403   if (SCM_I_GSC_HAVE_THREAD_STORAGE_CLASS)
 404     pf ("#define SCM_HAVE_THREAD_STORAGE_CLASS\n");
 405   else
 406     pf ("/* #undef SCM_HAVE_THREAD_STORAGE_CLASS */\n");
 407
 408 #ifdef USE_DLL_IMPORT
 409   pf ("\n");
 410   pf ("/* Define some additional CPP macros on Win32 platforms. */\n");
 411   pf ("# define __REGEX_IMPORT__ 1\n");
 412   pf ("# define __CRYPT_IMPORT__ 1\n");
 413   pf ("# define __READLINE_IMPORT__ 1\n");
 414   pf ("# define QT_IMPORT 1\n");
 415 #endif
 416
 417   pf ("\n");
 418   pf ("#if SCM_ENABLE_DEPRECATED == 1\n"
 419       "# define USE_THREADS 1 /* always true now */\n"
 420       "# define GUILE_ISELECT 1 /* always true now */\n"
 421       "# define READER_EXTENSIONS 1 /* always true now */\n"
 422       "# define DEBUG_EXTENSIONS 1 /* always true now */\n"
 423       "# define DYNAMIC_LINKING 1 /* always true now */\n"
 424       "#endif\n");
 425   printf ("\n");
 426
 427   pf ("#define SCM_HAVE_ARRAYS 1 /* always true now */\n");
 428
 429   pf ("\n");
 430   pf ("/* Constants from uniconv.h.  */\n");
 431   pf ("#define SCM_ICONVEH_ERROR %d\n", (int) iconveh_error);
 432   pf ("#define SCM_ICONVEH_QUESTION_MARK %d\n",
 433       (int) iconveh_question_mark);
 434   pf ("#define SCM_ICONVEH_ESCAPE_SEQUENCE %d\n",
 435       (int) iconveh_escape_sequence);
 436
 437   printf ("#endif\n");
 438
 439   return 0;
 440 }