Include/pyport.h

   1 #ifndef Py_PYPORT_H
   2 #define Py_PYPORT_H
   3
   4 #include "pyconfig.h" /* include for defines */
   5
   6 /**************************************************************************
   7 Symbols and macros to supply platform-independent interfaces to basic
   8 C language & library operations whose spellings vary across platforms.
   9
  10 Please try to make documentation here as clear as possible:  by definition,
  11 the stuff here is trying to illuminate C's darkest corners.
  12
  13 Config #defines referenced here:
  14
  15 SIGNED_RIGHT_SHIFT_ZERO_FILLS
  16 Meaning:  To be defined iff i>>j does not extend the sign bit when i is a
  17           signed integral type and i < 0.
  18 Used in:  Py_ARITHMETIC_RIGHT_SHIFT
  19
  20 Py_DEBUG
  21 Meaning:  Extra checks compiled in for debug mode.
  22 Used in:  Py_SAFE_DOWNCAST
  23
  24 HAVE_UINTPTR_T
  25 Meaning:  The C9X type uintptr_t is supported by the compiler
  26 Used in:  Py_uintptr_t
  27
  28 HAVE_LONG_LONG
  29 Meaning:  The compiler supports the C type "long long"
  30 Used in:  LONG_LONG
  31
  32 **************************************************************************/
  33
  34
  35 /* For backward compatibility only. Obsolete, do not use. */
  36 #define ANY void
  37 #ifdef HAVE_PROTOTYPES
  38 #define Py_PROTO(x) x
  39 #else
  40 #define Py_PROTO(x) ()
  41 #endif
  42 #ifndef Py_FPROTO
  43 #define Py_FPROTO(x) Py_PROTO(x)
  44 #endif
  45
  46 /* typedefs for some C9X-defined synonyms for integral types.
  47  *
  48  * The names in Python are exactly the same as the C9X names, except with a
  49  * Py_ prefix.  Until C9X is universally implemented, this is the only way
  50  * to ensure that Python gets reliable names that don't conflict with names
  51  * in non-Python code that are playing their own tricks to define the C9X
  52  * names.
  53  *
  54  * NOTE: don't go nuts here!  Python has no use for *most* of the C9X
  55  * integral synonyms.  Only define the ones we actually need.
  56  */
  57
  58 #ifdef HAVE_LONG_LONG
  59 #ifndef LONG_LONG
  60 #define LONG_LONG long long
  61 #endif
  62 #endif /* HAVE_LONG_LONG */
  63
  64 /* uintptr_t is the C9X name for an unsigned integral type such that a
  65  * legitimate void* can be cast to uintptr_t and then back to void* again
  66  * without loss of information.  Similarly for intptr_t, wrt a signed
  67  * integral type.
  68  */
  69 #ifdef HAVE_UINTPTR_T
  70 typedef uintptr_t       Py_uintptr_t;
  71 typedef intptr_t        Py_intptr_t;
  72
  73 #elif SIZEOF_VOID_P <= SIZEOF_INT
  74 typedef unsigned int    Py_uintptr_t;
  75 typedef int             Py_intptr_t;
  76
  77 #elif SIZEOF_VOID_P <= SIZEOF_LONG
  78 typedef unsigned long   Py_uintptr_t;
  79 typedef long            Py_intptr_t;
  80
  81 #elif defined(HAVE_LONG_LONG) && (SIZEOF_VOID_P <= SIZEOF_LONG_LONG)
  82 typedef unsigned LONG_LONG      Py_uintptr_t;
  83 typedef LONG_LONG               Py_intptr_t;
  84
  85 #else
  86 #   error "Python needs a typedef for Py_uintptr_t in pyport.h."
  87 #endif /* HAVE_UINTPTR_T */
  88
  89 #ifdef HAVE_STDLIB_H
  90 #include <stdlib.h>
  91 #endif
  92
  93 #include <math.h> /* Moved here from the math section, before extern "C" */
  94
  95 /********************************************
  96  * WRAPPER FOR <time.h> and/or <sys/time.h> *
  97  ********************************************/
  98
  99 #ifdef TIME_WITH_SYS_TIME
 100 #include <sys/time.h>
 101 #include <time.h>
 102 #else /* !TIME_WITH_SYS_TIME */
 103 #ifdef HAVE_SYS_TIME_H
 104 #include <sys/time.h>
 105 #else /* !HAVE_SYS_TIME_H */
 106 #include <time.h>
 107 #endif /* !HAVE_SYS_TIME_H */
 108 #endif /* !TIME_WITH_SYS_TIME */
 109
 110
 111 /******************************
 112  * WRAPPER FOR <sys/select.h> *
 113  ******************************/
 114
 115 /* NB caller must include <sys/types.h> */
 116
 117 #ifdef HAVE_SYS_SELECT_H
 118
 119 #include <sys/select.h>
 120
 121 #else /* !HAVE_SYS_SELECT_H */
 122
 123 #ifdef USE_GUSI1
 124 /* If we don't have sys/select the definition may be in unistd.h */
 125 #include <GUSI.h>
 126 #endif
 127
 128 #endif /* !HAVE_SYS_SELECT_H */
 129
 130 /*******************************
 131  * stat() and fstat() fiddling *
 132  *******************************/
 133
 134 /* We expect that stat and fstat exist on most systems.
 135  *  It's confirmed on Unix, Mac and Windows.
 136  *  If you don't have them, add
 137  *      #define DONT_HAVE_STAT
 138  * and/or
 139  *      #define DONT_HAVE_FSTAT
 140  * to your pyconfig.h. Python code beyond this should check HAVE_STAT and
 141  * HAVE_FSTAT instead.
 142  * Also
 143  *      #define DONT_HAVE_SYS_STAT_H
 144  * if <sys/stat.h> doesn't exist on your platform, and
 145  *      #define HAVE_STAT_H
 146  * if <stat.h> does (don't look at me -- ths mess is inherited).
 147  */
 148 #ifndef DONT_HAVE_STAT
 149 #define HAVE_STAT
 150 #endif
 151
 152 #ifndef DONT_HAVE_FSTAT
 153 #define HAVE_FSTAT
 154 #endif
 155
 156 #ifdef RISCOS
 157 #include <sys/types.h>
 158 #endif
 159
 160 #ifndef DONT_HAVE_SYS_STAT_H
 161 #include <sys/stat.h>
 162 #elif defined(HAVE_STAT_H)
 163 #include <stat.h>
 164 #endif
 165
 166 #if defined(PYCC_VACPP)
 167 /* VisualAge C/C++ Failed to Define MountType Field in sys/stat.h */
 168 #define S_IFMT (S_IFDIR|S_IFCHR|S_IFREG)
 169 #endif
 170
 171 #ifndef S_ISREG
 172 #define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)
 173 #endif
 174
 175 #ifndef S_ISDIR
 176 #define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR)
 177 #endif
 178
 179
 180 #ifdef __cplusplus
 181 /* Move this down here since some C++ #include's don't like to be included
 182    inside an extern "C" */
 183 extern "C" {
 184 #endif
 185
 186
 187 /* Py_ARITHMETIC_RIGHT_SHIFT
 188  * C doesn't define whether a right-shift of a signed integer sign-extends
 189  * or zero-fills.  Here a macro to force sign extension:
 190  * Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J)
 191  *    Return I >> J, forcing sign extension.
 192  * Requirements:
 193  *    I is of basic signed type TYPE (char, short, int, long, or long long).
 194  *    TYPE is one of char, short, int, long, or long long, although long long
 195  *    must not be used except on platforms that support it.
 196  *    J is an integer >= 0 and strictly less than the number of bits in TYPE
 197  *    (because C doesn't define what happens for J outside that range either).
 198  * Caution:
 199  *    I may be evaluated more than once.
 200  */
 201 #ifdef SIGNED_RIGHT_SHIFT_ZERO_FILLS
 202 #define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) \
 203         ((I) < 0 ? ~((~(unsigned TYPE)(I)) >> (J)) : (I) >> (J))
 204 #else
 205 #define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) ((I) >> (J))
 206 #endif
 207
 208 /* Py_FORCE_EXPANSION(X)
 209  * "Simply" returns its argument.  However, macro expansions within the
 210  * argument are evaluated.  This unfortunate trickery is needed to get
 211  * token-pasting to work as desired in some cases.
 212  */
 213 #define Py_FORCE_EXPANSION(X) X
 214
 215 /* Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW)
 216  * Cast VALUE to type NARROW from type WIDE.  In Py_DEBUG mode, this
 217  * assert-fails if any information is lost.
 218  * Caution:
 219  *    VALUE may be evaluated more than once.
 220  */
 221 #ifdef Py_DEBUG
 222 #define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) \
 223         (assert((WIDE)(NARROW)(VALUE) == (VALUE)), (NARROW)(VALUE))
 224 #else
 225 #define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) (NARROW)(VALUE)
 226 #endif
 227
 228 /* Py_IS_INFINITY(X)
 229  * Return 1 if float or double arg is an infinity, else 0.
 230  * Caution:
 231  *    X is evaluated more than once.
 232  *    This implementation may set the underflow flag if |X| is very small;
 233  *    it really can't be implemented correctly (& easily) before C99.
 234  */
 235 #define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))
 236
 237 /* According to
 238  * http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
 239  * on some Cray systems HUGE_VAL is incorrectly (according to the C std)
 240  * defined to be the largest positive finite rather than infinity.  We need
 241  * the std-conforming infinity meaning (provided the platform has one!).
 242  *
 243  * Then, according to a bug report on SourceForge, defining Py_HUGE_VAL as
 244  * INFINITY caused internal compiler errors under BeOS using some version
 245  * of gcc.  Explicitly casting INFINITY to double made that problem go away.
 246  */
 247 #ifdef INFINITY
 248 #define Py_HUGE_VAL ((double)INFINITY)
 249 #else
 250 #define Py_HUGE_VAL HUGE_VAL
 251 #endif
 252
 253 /* Py_OVERFLOWED(X)
 254  * Return 1 iff a libm function overflowed.  Set errno to 0 before calling
 255  * a libm function, and invoke this macro after, passing the function
 256  * result.
 257  * Caution:
 258  *    This isn't reliable.  C99 no longer requires libm to set errno under
 259  *        any exceptional condition, but does require +- HUGE_VAL return
 260  *        values on overflow.  A 754 box *probably* maps HUGE_VAL to a
 261  *        double infinity, and we're cool if that's so, unless the input
 262  *        was an infinity and an infinity is the expected result.  A C89
 263  *        system sets errno to ERANGE, so we check for that too.  We're
 264  *        out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
 265  *        if the returned result is a NaN, or if a C89 box returns HUGE_VAL
 266  *        in non-overflow cases.
 267  *    X is evaluated more than once.
 268  */
 269 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE ||    \
 270                                          (X) == Py_HUGE_VAL || \
 271                                          (X) == -Py_HUGE_VAL))
 272
 273 /* Py_SET_ERANGE_ON_OVERFLOW(x)
 274  * If a libm function did not set errno, but it looks like the result
 275  * overflowed, set errno to ERANGE.  Set errno to 0 before calling a libm
 276  * function, and invoke this macro after, passing the function result.
 277  * Caution:
 278  *    This isn't reliable.  See Py_OVERFLOWED comments.
 279  *    X is evaluated more than once.
 280  */
 281 #define Py_SET_ERANGE_IF_OVERFLOW(X) \
 282         do { \
 283                 if (errno == 0 && ((X) == Py_HUGE_VAL ||  \
 284                                    (X) == -Py_HUGE_VAL))  \
 285                         errno = ERANGE; \
 286         } while(0)
 287
 288 /* Py_ADJUST_ERANGE1(x)
 289  * Py_ADJUST_ERANGE2(x, y)
 290  * Set errno to 0 before calling a libm function, and invoke one of these
 291  * macros after, passing the function result(s) (Py_ADJUST_ERANGE2 is useful
 292  * for functions returning complex results).  This makes two kinds of
 293  * adjustments to errno:  (A) If it looks like the platform libm set
 294  * errno=ERANGE due to underflow, clear errno. (B) If it looks like the
 295  * platform libm overflowed but didn't set errno, force errno to ERANGE.  In
 296  * effect, we're trying to force a useful implementation of C89 errno
 297  * behavior.
 298  * Caution:
 299  *    This isn't reliable.  See Py_OVERFLOWED comments.
 300  *    X and Y may be evaluated more than once.
 301  */
 302 #define Py_ADJUST_ERANGE1(X)                                            \
 303         do {                                                            \
 304                 if (errno == 0) {                                       \
 305                         if ((X) == Py_HUGE_VAL || (X) == -Py_HUGE_VAL)  \
 306                                 errno = ERANGE;                         \
 307                 }                                                       \
 308                 else if (errno == ERANGE && (X) == 0.0)                 \
 309                         errno = 0;                                      \
 310         } while(0)
 311
 312 #define Py_ADJUST_ERANGE2(X, Y)                                         \
 313         do {                                                            \
 314                 if ((X) == Py_HUGE_VAL || (X) == -Py_HUGE_VAL ||        \
 315                     (Y) == Py_HUGE_VAL || (Y) == -Py_HUGE_VAL) {        \
 316                                 if (errno == 0)                         \
 317                                         errno = ERANGE;                 \
 318                 }                                                       \
 319                 else if (errno == ERANGE)                               \
 320                         errno = 0;                                      \
 321         } while(0)
 322
 323 /**************************************************************************
 324 Prototypes that are missing from the standard include files on some systems
 325 (and possibly only some versions of such systems.)
 326
 327 Please be conservative with adding new ones, document them and enclose them
 328 in platform-specific #ifdefs.
 329 **************************************************************************/
 330
 331 #ifdef SOLARIS
 332 /* Unchecked */
 333 extern int gethostname(char *, int);
 334 #endif
 335
 336 #ifdef __BEOS__
 337 /* Unchecked */
 338 /* It's in the libs, but not the headers... - [cjh] */
 339 int shutdown( int, int );
 340 #endif
 341
 342 #ifdef HAVE__GETPTY
 343 #include <sys/types.h>          /* we need to import mode_t */
 344 extern char * _getpty(int *, int, mode_t, int);
 345 #endif
 346
 347 #if defined(HAVE_OPENPTY) || defined(HAVE_FORKPTY)
 348 #if !defined(HAVE_PTY_H) && !defined(HAVE_LIBUTIL_H)
 349 /* BSDI does not supply a prototype for the 'openpty' and 'forkpty'
 350    functions, even though they are included in libutil. */
 351 #include <termios.h>
 352 extern int openpty(int *, int *, char *, struct termios *, struct winsize *);
 353 extern int forkpty(int *, char *, struct termios *, struct winsize *);
 354 #endif /* !defined(HAVE_PTY_H) && !defined(HAVE_LIBUTIL_H) */
 355 #endif /* defined(HAVE_OPENPTY) || defined(HAVE_FORKPTY) */
 356
 357
 358 /* These are pulled from various places. It isn't obvious on what platforms
 359    they are necessary, nor what the exact prototype should look like (which
 360    is likely to vary between platforms!) If you find you need one of these
 361    declarations, please move them to a platform-specific block and include
 362    proper prototypes. */
 363 #if 0
 364
 365 /* From Modules/resource.c */
 366 extern int getrusage();
 367 extern int getpagesize();
 368
 369 /* From Python/sysmodule.c and Modules/posixmodule.c */
 370 extern int fclose(FILE *);
 371
 372 /* From Modules/posixmodule.c */
 373 extern int fdatasync(int);
 374 /* XXX These are supposedly for SunOS4.1.3 but "shouldn't hurt elsewhere" */
 375 extern int rename(const char *, const char *);
 376 extern int pclose(FILE *);
 377 extern int lstat(const char *, struct stat *);
 378 extern int symlink(const char *, const char *);
 379 extern int fsync(int fd);
 380
 381 #endif /* 0 */
 382
 383
 384 /************************
 385  * WRAPPER FOR <math.h> *
 386  ************************/
 387
 388 #ifndef HAVE_HYPOT
 389 extern double hypot(double, double);
 390 #endif
 391
 392
 393 /************************************
 394  * MALLOC COMPATIBILITY FOR pymem.h *
 395  ************************************/
 396
 397 #ifndef DL_IMPORT       /* declarations for DLL import */
 398 #define DL_IMPORT(RTYPE) RTYPE
 399 #endif
 400
 401 #ifdef MALLOC_ZERO_RETURNS_NULL
 402 /* Allocate an extra byte if the platform malloc(0) returns NULL.
 403    Caution:  this bears no relation to whether realloc(p, 0) returns NULL
 404    when p != NULL.  Even on platforms where malloc(0) does not return NULL,
 405    realloc(p, 0) may act like free(p) and return NULL.  Examples include
 406    Windows, and Python's own obmalloc.c (as of 2-Mar-2002).  For whatever
 407    reason, our docs promise that PyMem_Realloc(p, 0) won't act like
 408    free(p) or return NULL, so realloc() calls may have to be hacked
 409    too, but MALLOC_ZERO_RETURNS_NULL's state is irrelevant to realloc (it
 410    needs a different hack).
 411 */
 412 #define _PyMem_EXTRA 1
 413 #else
 414 #define _PyMem_EXTRA 0
 415 #endif
 416
 417
 418 /* If the fd manipulation macros aren't defined,
 419    here is a set that should do the job */
 420
 421 #if 0 /* disabled and probably obsolete */
 422
 423 #ifndef FD_SETSIZE
 424 #define FD_SETSIZE      256
 425 #endif
 426
 427 #ifndef FD_SET
 428
 429 typedef long fd_mask;
 430
 431 #define NFDBITS (sizeof(fd_mask) * NBBY)        /* bits per mask */
 432 #ifndef howmany
 433 #define howmany(x, y)   (((x)+((y)-1))/(y))
 434 #endif /* howmany */
 435
 436 typedef struct fd_set {
 437         fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
 438 } fd_set;
 439
 440 #define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
 441 #define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
 442 #define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
 443 #define FD_ZERO(p)      memset((char *)(p), '\0', sizeof(*(p)))
 444
 445 #endif /* FD_SET */
 446
 447 #endif /* fd manipulation macros */
 448
 449
 450 /* limits.h constants that may be missing */
 451
 452 #ifndef INT_MAX
 453 #define INT_MAX 2147483647
 454 #endif
 455
 456 #ifndef LONG_MAX
 457 #if SIZEOF_LONG == 4
 458 #define LONG_MAX 0X7FFFFFFFL
 459 #elif SIZEOF_LONG == 8
 460 #define LONG_MAX 0X7FFFFFFFFFFFFFFFL
 461 #else
 462 #error "could not set LONG_MAX in pyport.h"
 463 #endif
 464 #endif
 465
 466 #ifndef LONG_MIN
 467 #define LONG_MIN (-LONG_MAX-1)
 468 #endif
 469
 470 #ifndef LONG_BIT
 471 #define LONG_BIT (8 * SIZEOF_LONG)
 472 #endif
 473
 474 #if LONG_BIT != 8 * SIZEOF_LONG
 475 /* 04-Oct-2000 LONG_BIT is apparently (mis)defined as 64 on some recent
 476  * 32-bit platforms using gcc.  We try to catch that here at compile-time
 477  * rather than waiting for integer multiplication to trigger bogus
 478  * overflows.
 479  */
 480 #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
 481 #endif
 482
 483 /*
 484  * Rename some functions for the Borland compiler
 485  */
 486 #ifdef __BORLANDC__
 487 #  include <io.h>
 488 #  define _chsize chsize
 489 #  define _setmode setmode
 490 #endif
 491
 492 #ifdef __cplusplus
 493 }
 494 #endif
 495
 496 /*
 497  * Hide GCC attributes from compilers that don't support them.
 498  */
 499 #if (!defined(__GNUC__) || __GNUC__ < 2 || \
 500      (__GNUC__ == 2 && __GNUC_MINOR__ < 7) || \
 501      defined(NEXT) ) && \
 502     !defined(RISCOS)
 503 #define __attribute__(__x)
 504 #endif
 505
 506 #endif /* Py_PYPORT_H */