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 #ifdef HAVE_PROTOTYPES
  37 #define Py_PROTO(x) x
  38 #else
  39 #define Py_PROTO(x) ()
  40 #endif
  41 #ifndef Py_FPROTO
  42 #define Py_FPROTO(x) Py_PROTO(x)
  43 #endif
  44
  45 /* typedefs for some C9X-defined synonyms for integral types.
  46  *
  47  * The names in Python are exactly the same as the C9X names, except with a
  48  * Py_ prefix.  Until C9X is universally implemented, this is the only way
  49  * to ensure that Python gets reliable names that don't conflict with names
  50  * in non-Python code that are playing their own tricks to define the C9X
  51  * names.
  52  *
  53  * NOTE: don't go nuts here!  Python has no use for *most* of the C9X
  54  * integral synonyms.  Only define the ones we actually need.
  55  */
  56
  57 #ifdef HAVE_LONG_LONG
  58 #ifndef LONG_LONG
  59 #define LONG_LONG long long
  60 #endif
  61 #endif /* HAVE_LONG_LONG */
  62
  63 /* uintptr_t is the C9X name for an unsigned integral type such that a
  64  * legitimate void* can be cast to uintptr_t and then back to void* again
  65  * without loss of information.  Similarly for intptr_t, wrt a signed
  66  * integral type.
  67  */
  68 #ifdef HAVE_UINTPTR_T
  69 typedef uintptr_t       Py_uintptr_t;
  70 typedef intptr_t        Py_intptr_t;
  71
  72 #elif SIZEOF_VOID_P <= SIZEOF_INT
  73 typedef unsigned int    Py_uintptr_t;
  74 typedef int             Py_intptr_t;
  75
  76 #elif SIZEOF_VOID_P <= SIZEOF_LONG
  77 typedef unsigned long   Py_uintptr_t;
  78 typedef long            Py_intptr_t;
  79
  80 #elif defined(HAVE_LONG_LONG) && (SIZEOF_VOID_P <= SIZEOF_LONG_LONG)
  81 typedef unsigned LONG_LONG      Py_uintptr_t;
  82 typedef LONG_LONG               Py_intptr_t;
  83
  84 #else
  85 #   error "Python needs a typedef for Py_uintptr_t in pyport.h."
  86 #endif /* HAVE_UINTPTR_T */
  87
  88 #ifdef HAVE_STDLIB_H
  89 #include <stdlib.h>
  90 #endif
  91
  92 #include <math.h> /* Moved here from the math section, before extern "C" */
  93
  94 /********************************************
  95  * WRAPPER FOR <time.h> and/or <sys/time.h> *
  96  ********************************************/
  97
  98 #ifdef TIME_WITH_SYS_TIME
  99 #include <sys/time.h>
 100 #include <time.h>
 101 #else /* !TIME_WITH_SYS_TIME */
 102 #ifdef HAVE_SYS_TIME_H
 103 #include <sys/time.h>
 104 #else /* !HAVE_SYS_TIME_H */
 105 #include <time.h>
 106 #endif /* !HAVE_SYS_TIME_H */
 107 #endif /* !TIME_WITH_SYS_TIME */
 108
 109
 110 /******************************
 111  * WRAPPER FOR <sys/select.h> *
 112  ******************************/
 113
 114 /* NB caller must include <sys/types.h> */
 115
 116 #ifdef HAVE_SYS_SELECT_H
 117
 118 #include <sys/select.h>
 119
 120 #endif /* !HAVE_SYS_SELECT_H */
 121
 122 /*******************************
 123  * stat() and fstat() fiddling *
 124  *******************************/
 125
 126 /* We expect that stat and fstat exist on most systems.
 127  *  It's confirmed on Unix, Mac and Windows.
 128  *  If you don't have them, add
 129  *      #define DONT_HAVE_STAT
 130  * and/or
 131  *      #define DONT_HAVE_FSTAT
 132  * to your pyconfig.h. Python code beyond this should check HAVE_STAT and
 133  * HAVE_FSTAT instead.
 134  * Also
 135  *      #define DONT_HAVE_SYS_STAT_H
 136  * if <sys/stat.h> doesn't exist on your platform, and
 137  *      #define HAVE_STAT_H
 138  * if <stat.h> does (don't look at me -- ths mess is inherited).
 139  */
 140 #ifndef DONT_HAVE_STAT
 141 #define HAVE_STAT
 142 #endif
 143
 144 #ifndef DONT_HAVE_FSTAT
 145 #define HAVE_FSTAT
 146 #endif
 147
 148 #ifdef RISCOS
 149 #include <sys/types.h>
 150 #endif
 151
 152 #ifndef DONT_HAVE_SYS_STAT_H
 153 #if defined(PYOS_OS2) && defined(PYCC_GCC)
 154 #include <sys/types.h>
 155 #endif
 156 #include <sys/stat.h>
 157 #elif defined(HAVE_STAT_H)
 158 #include <stat.h>
 159 #endif
 160
 161 #if defined(PYCC_VACPP)
 162 /* VisualAge C/C++ Failed to Define MountType Field in sys/stat.h */
 163 #define S_IFMT (S_IFDIR|S_IFCHR|S_IFREG)
 164 #endif
 165
 166 #ifndef S_ISREG
 167 #define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)
 168 #endif
 169
 170 #ifndef S_ISDIR
 171 #define S_ISDIR(x) (((x) & S_IFMT) == S_IFDIR)
 172 #endif
 173
 174
 175 #ifdef __cplusplus
 176 /* Move this down here since some C++ #include's don't like to be included
 177    inside an extern "C" */
 178 extern "C" {
 179 #endif
 180
 181
 182 /* Py_ARITHMETIC_RIGHT_SHIFT
 183  * C doesn't define whether a right-shift of a signed integer sign-extends
 184  * or zero-fills.  Here a macro to force sign extension:
 185  * Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J)
 186  *    Return I >> J, forcing sign extension.
 187  * Requirements:
 188  *    I is of basic signed type TYPE (char, short, int, long, or long long).
 189  *    TYPE is one of char, short, int, long, or long long, although long long
 190  *    must not be used except on platforms that support it.
 191  *    J is an integer >= 0 and strictly less than the number of bits in TYPE
 192  *    (because C doesn't define what happens for J outside that range either).
 193  * Caution:
 194  *    I may be evaluated more than once.
 195  */
 196 #ifdef SIGNED_RIGHT_SHIFT_ZERO_FILLS
 197 #define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) \
 198         ((I) < 0 ? ~((~(unsigned TYPE)(I)) >> (J)) : (I) >> (J))
 199 #else
 200 #define Py_ARITHMETIC_RIGHT_SHIFT(TYPE, I, J) ((I) >> (J))
 201 #endif
 202
 203 /* Py_FORCE_EXPANSION(X)
 204  * "Simply" returns its argument.  However, macro expansions within the
 205  * argument are evaluated.  This unfortunate trickery is needed to get
 206  * token-pasting to work as desired in some cases.
 207  */
 208 #define Py_FORCE_EXPANSION(X) X
 209
 210 /* Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW)
 211  * Cast VALUE to type NARROW from type WIDE.  In Py_DEBUG mode, this
 212  * assert-fails if any information is lost.
 213  * Caution:
 214  *    VALUE may be evaluated more than once.
 215  */
 216 #ifdef Py_DEBUG
 217 #define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) \
 218         (assert((WIDE)(NARROW)(VALUE) == (VALUE)), (NARROW)(VALUE))
 219 #else
 220 #define Py_SAFE_DOWNCAST(VALUE, WIDE, NARROW) (NARROW)(VALUE)
 221 #endif
 222
 223 /* Py_IS_INFINITY(X)
 224  * Return 1 if float or double arg is an infinity, else 0.
 225  * Caution:
 226  *    X is evaluated more than once.
 227  *    This implementation may set the underflow flag if |X| is very small;
 228  *    it really can't be implemented correctly (& easily) before C99.
 229  */
 230 #define Py_IS_INFINITY(X) ((X) && (X)*0.5 == (X))
 231
 232 /* According to
 233  * http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
 234  * on some Cray systems HUGE_VAL is incorrectly (according to the C std)
 235  * defined to be the largest positive finite rather than infinity.  We need
 236  * the std-conforming infinity meaning (provided the platform has one!).
 237  *
 238  * Then, according to a bug report on SourceForge, defining Py_HUGE_VAL as
 239  * INFINITY caused internal compiler errors under BeOS using some version
 240  * of gcc.  Explicitly casting INFINITY to double made that problem go away.
 241  */
 242 #ifdef INFINITY
 243 #define Py_HUGE_VAL ((double)INFINITY)
 244 #else
 245 #define Py_HUGE_VAL HUGE_VAL
 246 #endif
 247
 248 /* Py_OVERFLOWED(X)
 249  * Return 1 iff a libm function overflowed.  Set errno to 0 before calling
 250  * a libm function, and invoke this macro after, passing the function
 251  * result.
 252  * Caution:
 253  *    This isn't reliable.  C99 no longer requires libm to set errno under
 254  *        any exceptional condition, but does require +- HUGE_VAL return
 255  *        values on overflow.  A 754 box *probably* maps HUGE_VAL to a
 256  *        double infinity, and we're cool if that's so, unless the input
 257  *        was an infinity and an infinity is the expected result.  A C89
 258  *        system sets errno to ERANGE, so we check for that too.  We're
 259  *        out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
 260  *        if the returned result is a NaN, or if a C89 box returns HUGE_VAL
 261  *        in non-overflow cases.
 262  *    X is evaluated more than once.
 263  */
 264 #define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE ||    \
 265                                          (X) == Py_HUGE_VAL || \
 266                                          (X) == -Py_HUGE_VAL))
 267
 268 /* Py_SET_ERANGE_ON_OVERFLOW(x)
 269  * If a libm function did not set errno, but it looks like the result
 270  * overflowed, set errno to ERANGE.  Set errno to 0 before calling a libm
 271  * function, and invoke this macro after, passing the function result.
 272  * Caution:
 273  *    This isn't reliable.  See Py_OVERFLOWED comments.
 274  *    X is evaluated more than once.
 275  */
 276 #define Py_SET_ERANGE_IF_OVERFLOW(X) \
 277         do { \
 278                 if (errno == 0 && ((X) == Py_HUGE_VAL ||  \
 279                                    (X) == -Py_HUGE_VAL))  \
 280                         errno = ERANGE; \
 281         } while(0)
 282
 283 /* Py_ADJUST_ERANGE1(x)
 284  * Py_ADJUST_ERANGE2(x, y)
 285  * Set errno to 0 before calling a libm function, and invoke one of these
 286  * macros after, passing the function result(s) (Py_ADJUST_ERANGE2 is useful
 287  * for functions returning complex results).  This makes two kinds of
 288  * adjustments to errno:  (A) If it looks like the platform libm set
 289  * errno=ERANGE due to underflow, clear errno. (B) If it looks like the
 290  * platform libm overflowed but didn't set errno, force errno to ERANGE.  In
 291  * effect, we're trying to force a useful implementation of C89 errno
 292  * behavior.
 293  * Caution:
 294  *    This isn't reliable.  See Py_OVERFLOWED comments.
 295  *    X and Y may be evaluated more than once.
 296  */
 297 #define Py_ADJUST_ERANGE1(X)                                            \
 298         do {                                                            \
 299                 if (errno == 0) {                                       \
 300                         if ((X) == Py_HUGE_VAL || (X) == -Py_HUGE_VAL)  \
 301                                 errno = ERANGE;                         \
 302                 }                                                       \
 303                 else if (errno == ERANGE && (X) == 0.0)                 \
 304                         errno = 0;                                      \
 305         } while(0)
 306
 307 #define Py_ADJUST_ERANGE2(X, Y)                                         \
 308         do {                                                            \
 309                 if ((X) == Py_HUGE_VAL || (X) == -Py_HUGE_VAL ||        \
 310                     (Y) == Py_HUGE_VAL || (Y) == -Py_HUGE_VAL) {        \
 311                                 if (errno == 0)                         \
 312                                         errno = ERANGE;                 \
 313                 }                                                       \
 314                 else if (errno == ERANGE)                               \
 315                         errno = 0;                                      \
 316         } while(0)
 317
 318 /**************************************************************************
 319 Prototypes that are missing from the standard include files on some systems
 320 (and possibly only some versions of such systems.)
 321
 322 Please be conservative with adding new ones, document them and enclose them
 323 in platform-specific #ifdefs.
 324 **************************************************************************/
 325
 326 #ifdef SOLARIS
 327 /* Unchecked */
 328 extern int gethostname(char *, int);
 329 #endif
 330
 331 #ifdef __BEOS__
 332 /* Unchecked */
 333 /* It's in the libs, but not the headers... - [cjh] */
 334 int shutdown( int, int );
 335 #endif
 336
 337 #ifdef HAVE__GETPTY
 338 #include <sys/types.h>          /* we need to import mode_t */
 339 extern char * _getpty(int *, int, mode_t, int);
 340 #endif
 341
 342 #if defined(HAVE_OPENPTY) || defined(HAVE_FORKPTY)
 343 #if !defined(HAVE_PTY_H) && !defined(HAVE_LIBUTIL_H)
 344 /* BSDI does not supply a prototype for the 'openpty' and 'forkpty'
 345    functions, even though they are included in libutil. */
 346 #include <termios.h>
 347 extern int openpty(int *, int *, char *, struct termios *, struct winsize *);
 348 extern int forkpty(int *, char *, struct termios *, struct winsize *);
 349 #endif /* !defined(HAVE_PTY_H) && !defined(HAVE_LIBUTIL_H) */
 350 #endif /* defined(HAVE_OPENPTY) || defined(HAVE_FORKPTY) */
 351
 352
 353 /* These are pulled from various places. It isn't obvious on what platforms
 354    they are necessary, nor what the exact prototype should look like (which
 355    is likely to vary between platforms!) If you find you need one of these
 356    declarations, please move them to a platform-specific block and include
 357    proper prototypes. */
 358 #if 0
 359
 360 /* From Modules/resource.c */
 361 extern int getrusage();
 362 extern int getpagesize();
 363
 364 /* From Python/sysmodule.c and Modules/posixmodule.c */
 365 extern int fclose(FILE *);
 366
 367 /* From Modules/posixmodule.c */
 368 extern int fdatasync(int);
 369 /* XXX These are supposedly for SunOS4.1.3 but "shouldn't hurt elsewhere" */
 370 extern int rename(const char *, const char *);
 371 extern int pclose(FILE *);
 372 extern int lstat(const char *, struct stat *);
 373 extern int symlink(const char *, const char *);
 374 extern int fsync(int fd);
 375
 376 #endif /* 0 */
 377
 378
 379 /************************
 380  * WRAPPER FOR <math.h> *
 381  ************************/
 382
 383 #ifndef HAVE_HYPOT
 384 extern double hypot(double, double);
 385 #endif
 386
 387 #ifndef __CYGWIN__
 388 #ifndef DL_IMPORT       /* declarations for DLL import */
 389 #define DL_IMPORT(RTYPE) RTYPE
 390 #endif
 391 #else /* __CYGWIN__ */
 392 #ifdef USE_DL_IMPORT
 393 #define DL_IMPORT(RTYPE) __declspec(dllimport) RTYPE
 394 #define DL_EXPORT(RTYPE) __declspec(dllexport) RTYPE
 395 #else /* !USE_DL_IMPORT */
 396 #define DL_IMPORT(RTYPE) __declspec(dllexport) RTYPE
 397 #define DL_EXPORT(RTYPE) __declspec(dllexport) RTYPE
 398 #endif /* USE_DL_IMPORT */
 399 #endif /* __CYGWIN__ */
 400
 401 /* If the fd manipulation macros aren't defined,
 402    here is a set that should do the job */
 403
 404 #if 0 /* disabled and probably obsolete */
 405
 406 #ifndef FD_SETSIZE
 407 #define FD_SETSIZE      256
 408 #endif
 409
 410 #ifndef FD_SET
 411
 412 typedef long fd_mask;
 413
 414 #define NFDBITS (sizeof(fd_mask) * NBBY)        /* bits per mask */
 415 #ifndef howmany
 416 #define howmany(x, y)   (((x)+((y)-1))/(y))
 417 #endif /* howmany */
 418
 419 typedef struct fd_set {
 420         fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)];
 421 } fd_set;
 422
 423 #define FD_SET(n, p)    ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
 424 #define FD_CLR(n, p)    ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
 425 #define FD_ISSET(n, p)  ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
 426 #define FD_ZERO(p)      memset((char *)(p), '\0', sizeof(*(p)))
 427
 428 #endif /* FD_SET */
 429
 430 #endif /* fd manipulation macros */
 431
 432
 433 /* limits.h constants that may be missing */
 434
 435 #ifndef INT_MAX
 436 #define INT_MAX 2147483647
 437 #endif
 438
 439 #ifndef LONG_MAX
 440 #if SIZEOF_LONG == 4
 441 #define LONG_MAX 0X7FFFFFFFL
 442 #elif SIZEOF_LONG == 8
 443 #define LONG_MAX 0X7FFFFFFFFFFFFFFFL
 444 #else
 445 #error "could not set LONG_MAX in pyport.h"
 446 #endif
 447 #endif
 448
 449 #ifndef LONG_MIN
 450 #define LONG_MIN (-LONG_MAX-1)
 451 #endif
 452
 453 #ifndef LONG_BIT
 454 #define LONG_BIT (8 * SIZEOF_LONG)
 455 #endif
 456
 457 #if LONG_BIT != 8 * SIZEOF_LONG
 458 /* 04-Oct-2000 LONG_BIT is apparently (mis)defined as 64 on some recent
 459  * 32-bit platforms using gcc.  We try to catch that here at compile-time
 460  * rather than waiting for integer multiplication to trigger bogus
 461  * overflows.
 462  */
 463 #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
 464 #endif
 465
 466 /*
 467  * Rename some functions for the Borland compiler
 468  */
 469 #ifdef __BORLANDC__
 470 #  include <io.h>
 471 #  define _chsize chsize
 472 #  define _setmode setmode
 473 #endif
 474
 475 #ifdef __cplusplus
 476 }
 477 #endif
 478
 479 /*
 480  * Hide GCC attributes from compilers that don't support them.
 481  */
 482 #if (!defined(__GNUC__) || __GNUC__ < 2 || \
 483      (__GNUC__ == 2 && __GNUC_MINOR__ < 7) ) && \
 484     !defined(RISCOS)
 485 #define __attribute__(__x)
 486 #endif
 487
 488 #endif /* Py_PYPORT_H */