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 exception to this rule
  41      is GUILE_DEBUG which does not follow this convention in order to
  42      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.
  82
  83    Rationales (not finished):
  84
  85      Why do we use a C program here rather than AC_OUTPUT_COMMANDS?
  86      --------------------------------------------------------------
  87
  88      The main reason is that there are some values we would need
  89      access to at AC_OUTPUT_COMMANDs that are determined by configure
  90      but are not available at AC_OUTPUT time.  The values are *only*
  91      available via config.h.  We use gen-scmconfig so we can see those
  92      values and make decisions based on their settings.
  93
  94      Why have gen-scmconfig.h.in?
  95      ----------------------------
  96
  97      Without that header, we could end up needing multiple aliases for
  98      public settings like SCM_ENABLE_ELISP.  We can't define
  99      SCM_ENABLE_ELISP in config.h since that header is private and any
 100      definition in scmconfig.h would conflict (#ifndef might be
 101      possible but runs the risk of conflicting directives), so a
 102      likely solution would be to AC_DEFINE([SCM_I_ENABLE_ELISP]), and
 103      then use SCM_I_ENABLE_ELISP in gen-scmconfig via config.h to
 104      determine whether or not to #define SCM_ENABLE_ELISP, but this
 105      leaves us with two #defined symbols for each public setting --
 106      better to just have one value (public or private) that all code
 107      uses.
 108
 109      Having this header means we can AC_SUBST a value like
 110      SCM_I_GSC_ENABLE_ELISP and then set it in here via AC_OUTPUT
 111      substitutions, and gen-scmconfig can use that definition to
 112      determine whether or not to #define SCM_ENABLE_ELISP when
 113      generating scmconfig.h, and we end up with nothing extraneous
 114      added to config.h.
 115
 116  **********************************************************************/
 117
 118 #ifdef HAVE_CONFIG_H
 119 #  include <config.h>
 120 #endif
 121
 122 #include <libguile/gen-scmconfig.h>
 123
 124 #include <stdio.h>
 125 #include <string.h>
 126
 127 #define pf printf
 128
 129 int
 130 main (int argc, char *argv[])
 131 {
 132   pf ("/* This file is automatically generated --"
 133       " see configure.in for details */\n"
 134       "\n"
 135       "#ifndef SCM_SCMCONFIG_H\n"
 136       "#define SCM_SCMCONFIG_H\n");
 137
 138   /*** various important headers ***/
 139   pf ("\n");
 140   pf ("/* Important headers */\n");
 141   if (SCM_I_GSC_NEEDS_STDINT_H)
 142     pf ("#include <stdint.h>\n");
 143   if (SCM_I_GSC_NEEDS_INTTYPES_H)
 144     pf ("#include <inttypes.h>\n");
 145
 146 #ifdef HAVE_LIMITS_H
 147   pf ("#include <limits.h>\n");
 148 #else
 149   pf ("/* limits.h not available */\n");
 150 #endif
 151
 152 #if HAVE_SYS_TIME_H
 153   pf ("#include <sys/time.h>\n");
 154 #else
 155   pf ("/* sys/time.h not available */\n");
 156 #endif
 157
 158 #if HAVE_TIME_H
 159   pf ("#include <time.h>\n");
 160 #else
 161   pf ("/* time.h not available */\n");
 162 #endif
 163
 164   pf("\n");
 165 #ifdef STDC_HEADERS
 166   pf ("#define SCM_HAVE_STDC_HEADERS 1 /* 0 or 1 */\n");
 167   pf ("#include <stdlib.h>\n");
 168 # ifdef HAVE_SYS_TYPES_H
 169   pf ("#include <sys/types.h>\n");
 170 # endif
 171 # ifdef HAVE_SYS_STDTYPES_H
 172   pf ("#include <sys/stdtypes.h>\n");
 173 # endif
 174   pf ("#include <stddef.h>\n");
 175 #else /* STDC_HEADERS */
 176   pf ("#define SCM_HAVE_STDC_HEADERS 0 /* 0 or 1 */");
 177 #endif /* def STDC_HEADERS */
 178
 179   pf("\n");
 180 #ifdef HAVE_SYS_SELECT_H
 181   pf ("#define SCM_HAVE_SYS_SELECT_H 1 /* 0 or 1 */\n");
 182 #else
 183   pf ("#define SCM_HAVE_SYS_SELECT_H 0 /* 0 or 1 */\n");
 184 #endif
 185
 186 #ifdef HAVE_WINSOCK2_H
 187   pf ("#define SCM_HAVE_WINSOCK2_H 1 /* 0 or 1 */\n");
 188 #else
 189   pf ("#define SCM_HAVE_WINSOCK2_H 0 /* 0 or 1 */\n");
 190 #endif
 191
 192
 193   /*** GUILE_DEBUG (defined or undefined) ***/
 194   pf ("\n");
 195   pf ("/* Define to include various undocumented debugging functions. */\n");
 196   if (SCM_I_GSC_GUILE_DEBUG)
 197     pf ("#define GUILE_DEBUG 1 /* defined or undefined */\n");
 198   else
 199     pf ("/* #undef GUILE_DEBUG */\n");
 200
 201   /*** SCM_ENABLE_DEPRECATED (0 or 1) ***/
 202   pf ("\n");
 203   pf ("/* Set to 1 if you want to enable deprecated features. */\n");
 204   pf ("/* (value will be 0 or 1). */\n");
 205   pf ("#define SCM_ENABLE_DEPRECATED %d\n", SCM_I_GSC_ENABLE_DEPRECATED);
 206
 207   /*** SCM_STACK_GROWS_UP (0 or 1) ***/
 208   pf ("\n");
 209   pf ("/* Set to 1 if the stack grows up, 0 otherwise. */\n");
 210   pf ("#define SCM_STACK_GROWS_UP %d /* 0 or 1 */\n",
 211       SCM_I_GSC_STACK_GROWS_UP);
 212
 213   /*** SCM_C_INLINE (defined to appropriate string or undefined) ***/
 214   pf ("\n");
 215   pf ("/* C compiler's syntax for inline functions if any,\n"
 216       "   otherwise undefined. */\n");
 217   if (SCM_I_GSC_C_INLINE)
 218     pf ("#define SCM_C_INLINE %s\n", SCM_I_GSC_C_INLINE);
 219   else
 220     pf ("/* #undef SCM_C_INLINE */\n");
 221
 222   pf ("\n");
 223   pf ("/* Standard types. */\n");
 224
 225   pf ("/* These are always defined */\n");
 226   pf ("#define SCM_SIZEOF_CHAR %d\n", SIZEOF_CHAR);
 227   pf ("#define SCM_SIZEOF_UNSIGNED_CHAR %d\n", SIZEOF_UNSIGNED_CHAR);
 228   pf ("#define SCM_SIZEOF_SHORT %d\n", SIZEOF_SHORT);
 229   pf ("#define SCM_SIZEOF_UNSIGNED_SHORT %d\n", SIZEOF_UNSIGNED_SHORT);
 230   pf ("#define SCM_SIZEOF_LONG %d\n", SIZEOF_LONG);
 231   pf ("#define SCM_SIZEOF_UNSIGNED_LONG %d\n", SIZEOF_UNSIGNED_LONG);
 232   pf ("#define SCM_SIZEOF_INT %d\n", SIZEOF_INT);
 233   pf ("#define SCM_SIZEOF_UNSIGNED_INT %d\n", SIZEOF_UNSIGNED_INT);
 234   pf ("#define SCM_SIZEOF_SIZE_T %d\n", SIZEOF_SIZE_T);
 235
 236   pf ("\n");
 237   pf ("/* Size of (unsigned) long long or 0 if not available (scm_t_*64 may\n"
 238       "   be more likely to be what you want */\n");
 239   pf ("#define SCM_SIZEOF_LONG_LONG %d\n", SIZEOF_LONG_LONG);
 240   pf ("#define SCM_SIZEOF_UNSIGNED_LONG_LONG %d\n", SIZEOF_UNSIGNED_LONG_LONG);
 241
 242   pf ("\n");
 243   pf ("/* These are always defined. */\n");
 244   pf ("typedef %s scm_t_int8;\n", SCM_I_GSC_T_INT8);
 245   pf ("typedef %s scm_t_uint8;\n", SCM_I_GSC_T_UINT8);
 246   pf ("typedef %s scm_t_int16;\n", SCM_I_GSC_T_INT16);
 247   pf ("typedef %s scm_t_uint16;\n", SCM_I_GSC_T_UINT16);
 248   pf ("typedef %s scm_t_int32;\n", SCM_I_GSC_T_INT32);
 249   pf ("typedef %s scm_t_uint32;\n", SCM_I_GSC_T_UINT32);
 250   pf ("typedef %s scm_t_intmax;\n", SCM_I_GSC_T_INTMAX);
 251   pf ("typedef %s scm_t_uintmax;\n", SCM_I_GSC_T_UINTMAX);
 252   pf ("typedef %s scm_t_intptr;\n", SCM_I_GSC_T_INTPTR);
 253   pf ("typedef %s scm_t_uintptr;\n", SCM_I_GSC_T_UINTPTR);
 254
 255   if (0 == strcmp ("intmax_t", SCM_I_GSC_T_INTMAX))
 256     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF_INTMAX_T);
 257   else if (0 == strcmp ("long long", SCM_I_GSC_T_INTMAX))
 258     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF_LONG_LONG);
 259   else if (0 == strcmp ("__int64", SCM_I_GSC_T_INTMAX))
 260     pf ("#define SCM_SIZEOF_INTMAX %d\n", SIZEOF___INT64);
 261   else
 262     return 1;
 263
 264   pf ("\n");
 265   pf ("#define SCM_HAVE_T_INT64 1 /* 0 or 1 */\n");
 266   pf ("typedef %s scm_t_int64;\n", SCM_I_GSC_T_INT64);
 267   pf ("#define SCM_HAVE_T_UINT64 1 /* 0 or 1 */\n");
 268   pf ("typedef %s scm_t_uint64;\n", SCM_I_GSC_T_UINT64);
 269
 270   pf ("\n");
 271   pf ("/* scm_t_ptrdiff_t and size, always defined -- defined to long if\n"
 272       "   platform doesn't have ptrdiff_t. */\n");
 273   pf ("typedef %s scm_t_ptrdiff;\n", SCM_I_GSC_T_PTRDIFF);
 274   if (0 == strcmp ("long", SCM_I_GSC_T_PTRDIFF))
 275     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_LONG);
 276   else
 277     pf ("#define SCM_SIZEOF_SCM_T_PTRDIFF %d\n", SIZEOF_PTRDIFF_T);
 278
 279   pf ("\n");
 280   pf ("/* Size of intptr_t or 0 if not available */\n");
 281   pf ("#define SCM_SIZEOF_INTPTR_T %d\n", SIZEOF_INTPTR_T);
 282   pf ("/* Size of uintptr_t or 0 if not available */\n");
 283   pf ("#define SCM_SIZEOF_UINTPTR_T %d\n", SIZEOF_UINTPTR_T);
 284
 285   pf ("\n");
 286   pf ("/* same as POSIX \"struct timespec\" -- always defined */\n");
 287 #ifdef HAVE_STRUCT_TIMESPEC
 288   pf ("typedef struct timespec scm_t_timespec;\n");
 289 #else
 290   pf ("/* POSIX.4 structure for a time value.  This is like a `struct timeval'"
 291       "   but has nanoseconds instead of microseconds.  */\n");
 292   pf ("typedef struct\n"
 293       "{\n"
 294       "  long int tv_sec;               /* Seconds.  */\n"
 295       "  long int tv_nsec;              /* Nanoseconds.  */\n"
 296       "} scm_t_timespec;\n");
 297 #endif
 298
 299   pf ("\n");
 300   pf ("/*** Threading model (scmconfig.h support not finished) ***/\n");
 301
 302   pf ("/* Define to 1 if using pthread multithreading. */\n");
 303   pf ("#define SCM_USE_PTHREAD_THREADS %d /* 0 or 1 */\n",
 304       SCM_I_GSC_USE_PTHREAD_THREADS);
 305
 306   pf ("/* Define to 1 if using one-thread 'multi'threading. */\n");
 307   pf ("#define SCM_USE_NULL_THREADS %d /* 0 or 1 */\n",
 308       SCM_I_GSC_USE_NULL_THREADS);
 309
 310   pf ("/* Define to 1 if need braces around PTHREAD_ONCE_INIT (for Solaris). */\n");
 311   pf ("#define SCM_NEED_BRACES_ON_PTHREAD_ONCE_INIT %d /* 0 or 1 */\n",
 312       SCM_I_GSC_NEED_BRACES_ON_PTHREAD_ONCE_INIT);
 313
 314   pf ("/* Define to 1 if need braces around PTHREAD_MUTEX_INITIALIZER\n"
 315       "   (for IRIX with GCC)  */\n");
 316   pf ("#define SCM_NEED_BRACES_ON_PTHREAD_MUTEX_INITIALIZER %d /* 0 or 1 */\n",
 317       SCM_I_GSC_NEED_BRACES_ON_PTHREAD_MUTEX_INITIALIZER);
 318
 319 #ifdef HAVE_GC_PTHREAD_CANCEL
 320   pf ("#define SCM_HAVE_GC_PTHREAD_CANCEL 1 /* 0 or 1 */\n");
 321 #else
 322   pf ("#define SCM_HAVE_GC_PTHREAD_CANCEL 0 /* 0 or 1 */\n");
 323 #endif
 324
 325 #ifdef HAVE_GC_PTHREAD_EXIT
 326   pf ("#define SCM_HAVE_GC_PTHREAD_EXIT 1 /* 0 or 1 */\n");
 327 #else
 328   pf ("#define SCM_HAVE_GC_PTHREAD_EXIT 0 /* 0 or 1 */\n");
 329 #endif
 330
 331 #ifdef HAVE_GC_PTHREAD_SIGMASK
 332   pf ("#define SCM_HAVE_GC_PTHREAD_SIGMASK 1 /* 0 or 1 */\n");
 333 #else
 334   pf ("#define SCM_HAVE_GC_PTHREAD_SIGMASK 0 /* 0 or 1 */\n");
 335 #endif
 336
 337   pf ("\n\n/*** File system access ***/\n");
 338
 339   pf ("/* Define to 1 if `struct dirent64' is available.  */\n");
 340   pf ("#define SCM_HAVE_STRUCT_DIRENT64 %d /* 0 or 1 */\n",
 341       SCM_I_GSC_HAVE_STRUCT_DIRENT64);
 342
 343   pf ("/* Define to 1 if `readdir64_r ()' is available.  */\n");
 344 #ifdef HAVE_READDIR64_R
 345   pf ("#define SCM_HAVE_READDIR64_R 1 /* 0 or 1 */\n");
 346 #else
 347   pf ("#define SCM_HAVE_READDIR64_R 0 /* 0 or 1 */\n");
 348 #endif
 349
 350   /* Arrange so that we have a file offset type that reflects the one
 351      used when compiling Guile, regardless of what the application's
 352      `_FILE_OFFSET_BITS' says.  See
 353      http://lists.gnu.org/archive/html/bug-guile/2009-06/msg00018.html
 354      for the original bug report.
 355
 356      Note that we can't define `scm_t_off' in terms of `off_t' or
 357      `off64_t' because they may or may not be available depending on
 358      how the application that uses Guile is compiled.  */
 359
 360 #if defined GUILE_USE_64_CALLS && defined HAVE_STAT64
 361   pf ("typedef scm_t_int64 scm_t_off;\n");
 362 #elif SIZEOF_OFF_T == SIZEOF_INT
 363   pf ("typedef int scm_t_off;\n");
 364 #else
 365   pf ("typedef long int scm_t_off;\n");
 366 #endif
 367
 368   pf ("/* Define to 1 if the compiler supports the "
 369       "`__thread' storage class.  */\n");
 370   if (SCM_I_GSC_HAVE_THREAD_STORAGE_CLASS)
 371     pf ("#define SCM_HAVE_THREAD_STORAGE_CLASS\n");
 372   else
 373     pf ("/* #undef SCM_HAVE_THREAD_STORAGE_CLASS */\n");
 374
 375 #ifdef USE_DLL_IMPORT
 376   pf ("\n");
 377   pf ("/* Define some additional CPP macros on Win32 platforms. */\n");
 378   pf ("# define __REGEX_IMPORT__ 1\n");
 379   pf ("# define __CRYPT_IMPORT__ 1\n");
 380   pf ("# define __READLINE_IMPORT__ 1\n");
 381   pf ("# define QT_IMPORT 1\n");
 382 #endif
 383
 384   pf ("\n");
 385   pf ("#define SCM_HAVE_ARRAYS 1 /* always true now */\n");
 386
 387   pf ("\n");
 388   pf ("/* Constants from uniconv.h.  */\n");
 389   pf ("#define SCM_ICONVEH_ERROR %d\n", SCM_I_GSC_ICONVEH_ERROR);
 390   pf ("#define SCM_ICONVEH_QUESTION_MARK %d\n",
 391       SCM_I_GSC_ICONVEH_QUESTION_MARK);
 392   pf ("#define SCM_ICONVEH_ESCAPE_SEQUENCE %d\n",
 393       SCM_I_GSC_ICONVEH_ESCAPE_SEQUENCE);
 394
 395   printf ("#endif\n");
 396
 397   return 0;
 398 }