src/include/c.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * c.h
   4  *        Fundamental C definitions.  This is included by every .c file in
   5  *        PostgreSQL (via either postgres.h or postgres_fe.h, as appropriate).
   6  *
   7  *        Note that the definitions here are not intended to be exposed to clients
   8  *        of the frontend interface libraries --- so we don't worry much about
   9  *        polluting the namespace with lots of stuff...
  10  *
  11  *
  12  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  13  * Portions Copyright (c) 1994, Regents of the University of California
  14  *
  15  * $PostgreSQL$
  16  *
  17  *-------------------------------------------------------------------------
  18  */
  19 /*
  20  *----------------------------------------------------------------
  21  *       TABLE OF CONTENTS
  22  *
  23  *              When adding stuff to this file, please try to put stuff
  24  *              into the relevant section, or add new sections as appropriate.
  25  *
  26  *        section       description
  27  *        -------       ------------------------------------------------
  28  *              0)              pg_config.h and standard system headers
  29  *              1)              hacks to cope with non-ANSI C compilers
  30  *              2)              bool, true, false, TRUE, FALSE, NULL
  31  *              3)              standard system types
  32  *              4)              IsValid macros for system types
  33  *              5)              offsetof, lengthof, endof, alignment
  34  *              6)              widely useful macros
  35  *              7)              random stuff
  36  *              8)              system-specific hacks
  37  *
  38  * NOTE: since this file is included by both frontend and backend modules, it's
  39  * almost certainly wrong to put an "extern" declaration here.  typedefs and
  40  * macros are the kind of thing that might go here.
  41  *
  42  *----------------------------------------------------------------
  43  */
  44 #ifndef C_H
  45 #define C_H
  46
  47 /*
  48  * We have to include stdlib.h here because it defines many of these macros
  49  * on some platforms, and we only want our definitions used if stdlib.h doesn't
  50  * have its own.  The same goes for stddef and stdarg if present.
  51  */
  52
  53 #include "pg_config.h"
  54 #include "pg_config_manual.h"   /* must be after pg_config.h */
  55 #if !defined(WIN32) && !defined(__CYGWIN__)             /* win32 will include further
  56                                                                                                  * down */
  57 #include "pg_config_os.h"               /* must be before any system header files */
  58 #endif
  59 #include "postgres_ext.h"
  60
  61 #if _MSC_VER >= 1400
  62 #define errcode __msvc_errcode
  63 #include <crtdefs.h>
  64 #undef errcode
  65 #endif
  66
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70 #include <stddef.h>
  71 #include <stdarg.h>
  72 #ifdef HAVE_STRINGS_H
  73 #include <strings.h>
  74 #endif
  75 #include <sys/types.h>
  76
  77 #include <errno.h>
  78 #if defined(WIN32) || defined(__CYGWIN__)
  79 #include <fcntl.h>                              /* ensure O_BINARY is available */
  80 #endif
  81 #ifdef HAVE_SUPPORTDEFS_H
  82 #include <SupportDefs.h>
  83 #endif
  84
  85 #if defined(WIN32) || defined(__CYGWIN__)
  86 /* We have to redefine some system functions after they are included above. */
  87 #include "pg_config_os.h"
  88 #endif
  89
  90 /* Must be before gettext() games below */
  91 #include <locale.h>
  92
  93 #define _(x) gettext(x)
  94
  95 #ifdef ENABLE_NLS
  96 #include <libintl.h>
  97 #else
  98 #define gettext(x) (x)
  99 #define dgettext(d,x) (x)
 100 #define ngettext(s,p,n) ((n) == 1 ? (s) : (p))
 101 #define dngettext(d,s,p,n) ((n) == 1 ? (s) : (p))
 102 #endif
 103
 104 /*
 105  *      Use this to mark string constants as needing translation at some later
 106  *      time, rather than immediately.  This is useful for cases where you need
 107  *      access to the original string and translated string, and for cases where
 108  *      immediate translation is not possible, like when initializing global
 109  *      variables.
 110  *              http://www.gnu.org/software/autoconf/manual/gettext/Special-cases.html
 111  */
 112 #define gettext_noop(x) (x)
 113
 114
 115 /* ----------------------------------------------------------------
 116  *                              Section 1: hacks to cope with non-ANSI C compilers
 117  *
 118  * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
 119  * ----------------------------------------------------------------
 120  */
 121
 122 /*
 123  * CppAsString
 124  *              Convert the argument to a string, using the C preprocessor.
 125  * CppConcat
 126  *              Concatenate two arguments together, using the C preprocessor.
 127  *
 128  * Note: the standard Autoconf macro AC_C_STRINGIZE actually only checks
 129  * whether #identifier works, but if we have that we likely have ## too.
 130  */
 131 #if defined(HAVE_STRINGIZE)
 132
 133 #define CppAsString(identifier) #identifier
 134 #define CppConcat(x, y)                 x##y
 135 #else                                                   /* !HAVE_STRINGIZE */
 136
 137 #define CppAsString(identifier) "identifier"
 138
 139 /*
 140  * CppIdentity -- On Reiser based cpp's this is used to concatenate
 141  *              two tokens.  That is
 142  *                              CppIdentity(A)B ==> AB
 143  *              We renamed it to _private_CppIdentity because it should not
 144  *              be referenced outside this file.  On other cpp's it
 145  *              produces  A  B.
 146  */
 147 #define _priv_CppIdentity(x)x
 148 #define CppConcat(x, y)                 _priv_CppIdentity(x)y
 149 #endif   /* !HAVE_STRINGIZE */
 150
 151 /*
 152  * dummyret is used to set return values in macros that use ?: to make
 153  * assignments.  gcc wants these to be void, other compilers like char
 154  */
 155 #ifdef __GNUC__                                 /* GNU cc */
 156 #define dummyret        void
 157 #else
 158 #define dummyret        char
 159 #endif
 160
 161 #ifndef __GNUC__
 162 #define __attribute__(_arg_)
 163 #endif
 164
 165 /* ----------------------------------------------------------------
 166  *                              Section 2:      bool, true, false, TRUE, FALSE, NULL
 167  * ----------------------------------------------------------------
 168  */
 169
 170 /*
 171  * bool
 172  *              Boolean value, either true or false.
 173  *
 174  * XXX for C++ compilers, we assume the compiler has a compatible
 175  * built-in definition of bool.
 176  */
 177
 178 #ifndef __cplusplus
 179
 180 #ifndef bool
 181 typedef char bool;
 182 #endif
 183
 184 #ifndef true
 185 #define true    ((bool) 1)
 186 #endif
 187
 188 #ifndef false
 189 #define false   ((bool) 0)
 190 #endif
 191 #endif   /* not C++ */
 192
 193 typedef bool *BoolPtr;
 194
 195 #ifndef TRUE
 196 #define TRUE    1
 197 #endif
 198
 199 #ifndef FALSE
 200 #define FALSE   0
 201 #endif
 202
 203 /*
 204  * NULL
 205  *              Null pointer.
 206  */
 207 #ifndef NULL
 208 #define NULL    ((void *) 0)
 209 #endif
 210
 211
 212 /* ----------------------------------------------------------------
 213  *                              Section 3:      standard system types
 214  * ----------------------------------------------------------------
 215  */
 216
 217 /*
 218  * Pointer
 219  *              Variable holding address of any memory resident object.
 220  *
 221  *              XXX Pointer arithmetic is done with this, so it can't be void *
 222  *              under "true" ANSI compilers.
 223  */
 224 typedef char *Pointer;
 225
 226 /*
 227  * intN
 228  *              Signed integer, EXACTLY N BITS IN SIZE,
 229  *              used for numerical computations and the
 230  *              frontend/backend protocol.
 231  */
 232 #ifndef HAVE_INT8
 233 typedef signed char int8;               /* == 8 bits */
 234 typedef signed short int16;             /* == 16 bits */
 235 typedef signed int int32;               /* == 32 bits */
 236 #endif   /* not HAVE_INT8 */
 237
 238 /*
 239  * uintN
 240  *              Unsigned integer, EXACTLY N BITS IN SIZE,
 241  *              used for numerical computations and the
 242  *              frontend/backend protocol.
 243  */
 244 #ifndef HAVE_UINT8
 245 typedef unsigned char uint8;    /* == 8 bits */
 246 typedef unsigned short uint16;  /* == 16 bits */
 247 typedef unsigned int uint32;    /* == 32 bits */
 248 #endif   /* not HAVE_UINT8 */
 249
 250 /*
 251  * bitsN
 252  *              Unit of bitwise operation, AT LEAST N BITS IN SIZE.
 253  */
 254 typedef uint8 bits8;                    /* >= 8 bits */
 255 typedef uint16 bits16;                  /* >= 16 bits */
 256 typedef uint32 bits32;                  /* >= 32 bits */
 257
 258 /*
 259  * 64-bit integers
 260  */
 261 #ifdef HAVE_LONG_INT_64
 262 /* Plain "long int" fits, use it */
 263
 264 #ifndef HAVE_INT64
 265 typedef long int int64;
 266 #endif
 267 #ifndef HAVE_UINT64
 268 typedef unsigned long int uint64;
 269 #endif
 270 #elif defined(HAVE_LONG_LONG_INT_64)
 271 /* We have working support for "long long int", use that */
 272
 273 #ifndef HAVE_INT64
 274 typedef long long int int64;
 275 #endif
 276 #ifndef HAVE_UINT64
 277 typedef unsigned long long int uint64;
 278 #endif
 279 #else                                                   /* not HAVE_LONG_INT_64 and not
 280                                                                  * HAVE_LONG_LONG_INT_64 */
 281
 282 /* Won't actually work, but fall back to long int so that code compiles */
 283 #ifndef HAVE_INT64
 284 typedef long int int64;
 285 #endif
 286 #ifndef HAVE_UINT64
 287 typedef unsigned long int uint64;
 288 #endif
 289
 290 #define INT64_IS_BUSTED
 291 #endif   /* not HAVE_LONG_INT_64 and not
 292                                                                  * HAVE_LONG_LONG_INT_64 */
 293
 294 /* Decide if we need to decorate 64-bit constants */
 295 #ifdef HAVE_LL_CONSTANTS
 296 #define INT64CONST(x)  ((int64) x##LL)
 297 #define UINT64CONST(x) ((uint64) x##ULL)
 298 #else
 299 #define INT64CONST(x)  ((int64) x)
 300 #define UINT64CONST(x) ((uint64) x)
 301 #endif
 302
 303
 304 /* Select timestamp representation (float8 or int64) */
 305 #if defined(USE_INTEGER_DATETIMES) && !defined(INT64_IS_BUSTED)
 306 #define HAVE_INT64_TIMESTAMP
 307 #endif
 308
 309 /* sig_atomic_t is required by ANSI C, but may be missing on old platforms */
 310 #ifndef HAVE_SIG_ATOMIC_T
 311 typedef int sig_atomic_t;
 312 #endif
 313
 314 /*
 315  * Size
 316  *              Size of any memory resident object, as returned by sizeof.
 317  */
 318 typedef size_t Size;
 319
 320 /*
 321  * Index
 322  *              Index into any memory resident array.
 323  *
 324  * Note:
 325  *              Indices are non negative.
 326  */
 327 typedef unsigned int Index;
 328
 329 /*
 330  * Offset
 331  *              Offset into any memory resident array.
 332  *
 333  * Note:
 334  *              This differs from an Index in that an Index is always
 335  *              non negative, whereas Offset may be negative.
 336  */
 337 typedef signed int Offset;
 338
 339 /*
 340  * Common Postgres datatype names (as used in the catalogs)
 341  */
 342 typedef int16 int2;
 343 typedef int32 int4;
 344 typedef float float4;
 345 typedef double float8;
 346
 347 /*
 348  * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
 349  * CommandId
 350  */
 351
 352 /* typedef Oid is in postgres_ext.h */
 353
 354 /*
 355  * regproc is the type name used in the include/catalog headers, but
 356  * RegProcedure is the preferred name in C code.
 357  */
 358 typedef Oid regproc;
 359 typedef regproc RegProcedure;
 360
 361 typedef uint32 TransactionId;
 362
 363 typedef uint32 LocalTransactionId;
 364
 365 typedef uint32 SubTransactionId;
 366
 367 #define InvalidSubTransactionId         ((SubTransactionId) 0)
 368 #define TopSubTransactionId                     ((SubTransactionId) 1)
 369
 370 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
 371 typedef TransactionId MultiXactId;
 372
 373 typedef uint32 MultiXactOffset;
 374
 375 typedef uint32 CommandId;
 376
 377 #define FirstCommandId  ((CommandId) 0)
 378
 379 /*
 380  * Array indexing support
 381  */
 382 #define MAXDIM 6
 383 typedef struct
 384 {
 385         int                     indx[MAXDIM];
 386 } IntArray;
 387
 388 /* ----------------
 389  *              Variable-length datatypes all share the 'struct varlena' header.
 390  *
 391  * NOTE: for TOASTable types, this is an oversimplification, since the value
 392  * may be compressed or moved out-of-line.      However datatype-specific routines
 393  * are mostly content to deal with de-TOASTed values only, and of course
 394  * client-side routines should never see a TOASTed value.  But even in a
 395  * de-TOASTed value, beware of touching vl_len_ directly, as its representation
 396  * is no longer convenient.  It's recommended that code always use the VARDATA,
 397  * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
 398  * the struct fields.  See postgres.h for details of the TOASTed form.
 399  * ----------------
 400  */
 401 struct varlena
 402 {
 403         char            vl_len_[4];             /* Do not touch this field directly! */
 404         char            vl_dat[1];
 405 };
 406
 407 #define VARHDRSZ                ((int32) sizeof(int32))
 408
 409 /*
 410  * These widely-used datatypes are just a varlena header and the data bytes.
 411  * There is no terminating null or anything like that --- the data length is
 412  * always VARSIZE(ptr) - VARHDRSZ.
 413  */
 414 typedef struct varlena bytea;
 415 typedef struct varlena text;
 416 typedef struct varlena BpChar;  /* blank-padded char, ie SQL char(n) */
 417 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
 418
 419 /*
 420  * Specialized array types.  These are physically laid out just the same
 421  * as regular arrays (so that the regular array subscripting code works
 422  * with them).  They exist as distinct types mostly for historical reasons:
 423  * they have nonstandard I/O behavior which we don't want to change for fear
 424  * of breaking applications that look at the system catalogs.  There is also
 425  * an implementation issue for oidvector: it's part of the primary key for
 426  * pg_proc, and we can't use the normal btree array support routines for that
 427  * without circularity.
 428  */
 429 typedef struct
 430 {
 431         int32           vl_len_;                /* these fields must match ArrayType! */
 432         int                     ndim;                   /* always 1 for int2vector */
 433         int32           dataoffset;             /* always 0 for int2vector */
 434         Oid                     elemtype;
 435         int                     dim1;
 436         int                     lbound1;
 437         int2            values[1];              /* VARIABLE LENGTH ARRAY */
 438 } int2vector;                                   /* VARIABLE LENGTH STRUCT */
 439
 440 typedef struct
 441 {
 442         int32           vl_len_;                /* these fields must match ArrayType! */
 443         int                     ndim;                   /* always 1 for oidvector */
 444         int32           dataoffset;             /* always 0 for oidvector */
 445         Oid                     elemtype;
 446         int                     dim1;
 447         int                     lbound1;
 448         Oid                     values[1];              /* VARIABLE LENGTH ARRAY */
 449 } oidvector;                                    /* VARIABLE LENGTH STRUCT */
 450
 451 /*
 452  * Representation of a Name: effectively just a C string, but null-padded to
 453  * exactly NAMEDATALEN bytes.  The use of a struct is historical.
 454  */
 455 typedef struct nameData
 456 {
 457         char            data[NAMEDATALEN];
 458 } NameData;
 459 typedef NameData *Name;
 460
 461 #define NameStr(name)   ((name).data)
 462
 463 /*
 464  * Support macros for escaping strings.  escape_backslash should be TRUE
 465  * if generating a non-standard-conforming string.      Prefixing a string
 466  * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
 467  * Beware of multiple evaluation of the "ch" argument!
 468  */
 469 #define SQL_STR_DOUBLE(ch, escape_backslash)    \
 470         ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
 471
 472 #define ESCAPE_STRING_SYNTAX    'E'
 473
 474 /* ----------------------------------------------------------------
 475  *                              Section 4:      IsValid macros for system types
 476  * ----------------------------------------------------------------
 477  */
 478 /*
 479  * BoolIsValid
 480  *              True iff bool is valid.
 481  */
 482 #define BoolIsValid(boolean)    ((boolean) == false || (boolean) == true)
 483
 484 /*
 485  * PointerIsValid
 486  *              True iff pointer is valid.
 487  */
 488 #define PointerIsValid(pointer) ((void*)(pointer) != NULL)
 489
 490 /*
 491  * PointerIsAligned
 492  *              True iff pointer is properly aligned to point to the given type.
 493  */
 494 #define PointerIsAligned(pointer, type) \
 495                 (((long)(pointer) % (sizeof (type))) == 0)
 496
 497 #define OidIsValid(objectId)  ((bool) ((objectId) != InvalidOid))
 498
 499 #define RegProcedureIsValid(p)  OidIsValid(p)
 500
 501
 502 /* ----------------------------------------------------------------
 503  *                              Section 5:      offsetof, lengthof, endof, alignment
 504  * ----------------------------------------------------------------
 505  */
 506 /*
 507  * offsetof
 508  *              Offset of a structure/union field within that structure/union.
 509  *
 510  *              XXX This is supposed to be part of stddef.h, but isn't on
 511  *              some systems (like SunOS 4).
 512  */
 513 #ifndef offsetof
 514 #define offsetof(type, field)   ((long) &((type *)0)->field)
 515 #endif   /* offsetof */
 516
 517 /*
 518  * lengthof
 519  *              Number of elements in an array.
 520  */
 521 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
 522
 523 /*
 524  * endof
 525  *              Address of the element one past the last in an array.
 526  */
 527 #define endof(array)    (&(array)[lengthof(array)])
 528
 529 /* ----------------
 530  * Alignment macros: align a length or address appropriately for a given type.
 531  * The fooALIGN() macros round up to a multiple of the required alignment,
 532  * while the fooALIGN_DOWN() macros round down.  The latter are more useful
 533  * for problems like "how many X-sized structures will fit in a page?".
 534  *
 535  * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
 536  * That case seems extremely unlikely to be needed in practice, however.
 537  * ----------------
 538  */
 539
 540 #define TYPEALIGN(ALIGNVAL,LEN)  \
 541         (((long) (LEN) + ((ALIGNVAL) - 1)) & ~((long) ((ALIGNVAL) - 1)))
 542
 543 #define SHORTALIGN(LEN)                 TYPEALIGN(ALIGNOF_SHORT, (LEN))
 544 #define INTALIGN(LEN)                   TYPEALIGN(ALIGNOF_INT, (LEN))
 545 #define LONGALIGN(LEN)                  TYPEALIGN(ALIGNOF_LONG, (LEN))
 546 #define DOUBLEALIGN(LEN)                TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
 547 #define MAXALIGN(LEN)                   TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
 548 /* MAXALIGN covers only built-in types, not buffers */
 549 #define BUFFERALIGN(LEN)                TYPEALIGN(ALIGNOF_BUFFER, (LEN))
 550
 551 #define TYPEALIGN_DOWN(ALIGNVAL,LEN)  \
 552         (((long) (LEN)) & ~((long) ((ALIGNVAL) - 1)))
 553
 554 #define SHORTALIGN_DOWN(LEN)    TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
 555 #define INTALIGN_DOWN(LEN)              TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
 556 #define LONGALIGN_DOWN(LEN)             TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
 557 #define DOUBLEALIGN_DOWN(LEN)   TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
 558 #define MAXALIGN_DOWN(LEN)              TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
 559
 560 /* ----------------------------------------------------------------
 561  *                              Section 6:      widely useful macros
 562  * ----------------------------------------------------------------
 563  */
 564 /*
 565  * Max
 566  *              Return the maximum of two numbers.
 567  */
 568 #define Max(x, y)               ((x) > (y) ? (x) : (y))
 569
 570 /*
 571  * Min
 572  *              Return the minimum of two numbers.
 573  */
 574 #define Min(x, y)               ((x) < (y) ? (x) : (y))
 575
 576 /*
 577  * Abs
 578  *              Return the absolute value of the argument.
 579  */
 580 #define Abs(x)                  ((x) >= 0 ? (x) : -(x))
 581
 582 /*
 583  * StrNCpy
 584  *      Like standard library function strncpy(), except that result string
 585  *      is guaranteed to be null-terminated --- that is, at most N-1 bytes
 586  *      of the source string will be kept.
 587  *      Also, the macro returns no result (too hard to do that without
 588  *      evaluating the arguments multiple times, which seems worse).
 589  *
 590  *      BTW: when you need to copy a non-null-terminated string (like a text
 591  *      datum) and add a null, do not do it with StrNCpy(..., len+1).  That
 592  *      might seem to work, but it fetches one byte more than there is in the
 593  *      text object.  One fine day you'll have a SIGSEGV because there isn't
 594  *      another byte before the end of memory.  Don't laugh, we've had real
 595  *      live bug reports from real live users over exactly this mistake.
 596  *      Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
 597  */
 598 #define StrNCpy(dst,src,len) \
 599         do \
 600         { \
 601                 char * _dst = (dst); \
 602                 Size _len = (len); \
 603 \
 604                 if (_len > 0) \
 605                 { \
 606                         strncpy(_dst, (src), _len); \
 607                         _dst[_len-1] = '\0'; \
 608                 } \
 609         } while (0)
 610
 611
 612 /* Get a bit mask of the bits set in non-long aligned addresses */
 613 #define LONG_ALIGN_MASK (sizeof(long) - 1)
 614
 615 /*
 616  * MemSet
 617  *      Exactly the same as standard library function memset(), but considerably
 618  *      faster for zeroing small word-aligned structures (such as parsetree nodes).
 619  *      This has to be a macro because the main point is to avoid function-call
 620  *      overhead.       However, we have also found that the loop is faster than
 621  *      native libc memset() on some platforms, even those with assembler
 622  *      memset() functions.  More research needs to be done, perhaps with
 623  *      MEMSET_LOOP_LIMIT tests in configure.
 624  */
 625 #define MemSet(start, val, len) \
 626         do \
 627         { \
 628                 /* must be void* because we don't know if it is integer aligned yet */ \
 629                 void   *_vstart = (void *) (start); \
 630                 int             _val = (val); \
 631                 Size    _len = (len); \
 632 \
 633                 if ((((long) _vstart) & LONG_ALIGN_MASK) == 0 && \
 634                         (_len & LONG_ALIGN_MASK) == 0 && \
 635                         _val == 0 && \
 636                         _len <= MEMSET_LOOP_LIMIT && \
 637                         /* \
 638                          *      If MEMSET_LOOP_LIMIT == 0, optimizer should find \
 639                          *      the whole "if" false at compile time. \
 640                          */ \
 641                         MEMSET_LOOP_LIMIT != 0) \
 642                 { \
 643                         long *_start = (long *) _vstart; \
 644                         long *_stop = (long *) ((char *) _start + _len); \
 645                         while (_start < _stop) \
 646                                 *_start++ = 0; \
 647                 } \
 648                 else \
 649                         memset(_vstart, _val, _len); \
 650         } while (0)
 651
 652 /*
 653  * MemSetAligned is the same as MemSet except it omits the test to see if
 654  * "start" is word-aligned.  This is okay to use if the caller knows a-priori
 655  * that the pointer is suitably aligned (typically, because he just got it
 656  * from palloc(), which always delivers a max-aligned pointer).
 657  */
 658 #define MemSetAligned(start, val, len) \
 659         do \
 660         { \
 661                 long   *_start = (long *) (start); \
 662                 int             _val = (val); \
 663                 Size    _len = (len); \
 664 \
 665                 if ((_len & LONG_ALIGN_MASK) == 0 && \
 666                         _val == 0 && \
 667                         _len <= MEMSET_LOOP_LIMIT && \
 668                         MEMSET_LOOP_LIMIT != 0) \
 669                 { \
 670                         long *_stop = (long *) ((char *) _start + _len); \
 671                         while (_start < _stop) \
 672                                 *_start++ = 0; \
 673                 } \
 674                 else \
 675                         memset(_start, _val, _len); \
 676         } while (0)
 677
 678
 679 /*
 680  * MemSetTest/MemSetLoop are a variant version that allow all the tests in
 681  * MemSet to be done at compile time in cases where "val" and "len" are
 682  * constants *and* we know the "start" pointer must be word-aligned.
 683  * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
 684  * MemSetAligned.  Beware of multiple evaluations of the arguments when using
 685  * this approach.
 686  */
 687 #define MemSetTest(val, len) \
 688         ( ((len) & LONG_ALIGN_MASK) == 0 && \
 689         (len) <= MEMSET_LOOP_LIMIT && \
 690         MEMSET_LOOP_LIMIT != 0 && \
 691         (val) == 0 )
 692
 693 #define MemSetLoop(start, val, len) \
 694         do \
 695         { \
 696                 long * _start = (long *) (start); \
 697                 long * _stop = (long *) ((char *) _start + (Size) (len)); \
 698         \
 699                 while (_start < _stop) \
 700                         *_start++ = 0; \
 701         } while (0)
 702
 703
 704 /* ----------------------------------------------------------------
 705  *                              Section 7:      random stuff
 706  * ----------------------------------------------------------------
 707  */
 708
 709 /* msb for char */
 710 #define HIGHBIT                                 (0x80)
 711 #define IS_HIGHBIT_SET(ch)              ((unsigned char)(ch) & HIGHBIT)
 712
 713 #define STATUS_OK                               (0)
 714 #define STATUS_ERROR                    (-1)
 715 #define STATUS_EOF                              (-2)
 716 #define STATUS_FOUND                    (1)
 717 #define STATUS_WAITING                  (2)
 718
 719
 720 /* gettext domain name mangling */
 721
 722 /*
 723  * To better support parallel installations of major PostgeSQL
 724  * versions as well as parallel installations of major library soname
 725  * versions, we mangle the gettext domain name by appending those
 726  * version numbers.  The coding rule ought to be that whereever the
 727  * domain name is mentioned as a literal, it must be wrapped into
 728  * PG_TEXTDOMAIN().  The macros below do not work on non-literals; but
 729  * that is somewhat intentional because it avoids having to worry
 730  * about multiple states of premangling and postmangling as the values
 731  * are being passed around.
 732  *
 733  * Make sure this matches the installation rules in nls-global.mk.
 734  */
 735
 736 /* need a second indirection because we want to stringize the macro value, not the name */
 737 #define CppAsString2(x) CppAsString(x)
 738
 739 #ifdef SO_MAJOR_VERSION
 740 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
 741 #else
 742 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
 743 #endif
 744
 745
 746 /* ----------------------------------------------------------------
 747  *                              Section 8: system-specific hacks
 748  *
 749  *              This should be limited to things that absolutely have to be
 750  *              included in every source file.  The port-specific header file
 751  *              is usually a better place for this sort of thing.
 752  * ----------------------------------------------------------------
 753  */
 754
 755 /*
 756  *      NOTE:  this is also used for opening text files.
 757  *      WIN32 treats Control-Z as EOF in files opened in text mode.
 758  *      Therefore, we open files in binary mode on Win32 so we can read
 759  *      literal control-Z.      The other affect is that we see CRLF, but
 760  *      that is OK because we can already handle those cleanly.
 761  */
 762 #if defined(WIN32) || defined(__CYGWIN__)
 763 #define PG_BINARY       O_BINARY
 764 #define PG_BINARY_A "ab"
 765 #define PG_BINARY_R "rb"
 766 #define PG_BINARY_W "wb"
 767 #else
 768 #define PG_BINARY       0
 769 #define PG_BINARY_A "a"
 770 #define PG_BINARY_R "r"
 771 #define PG_BINARY_W "w"
 772 #endif
 773
 774 /*
 775  * Provide prototypes for routines not present in a particular machine's
 776  * standard C library.
 777  */
 778
 779 #if !HAVE_DECL_SNPRINTF
 780 extern int
 781 snprintf(char *str, size_t count, const char *fmt,...)
 782 /* This extension allows gcc to check the format string */
 783 __attribute__((format(printf, 3, 4)));
 784 #endif
 785
 786 #if !HAVE_DECL_VSNPRINTF
 787 extern int      vsnprintf(char *str, size_t count, const char *fmt, va_list args);
 788 #endif
 789
 790 #if !defined(HAVE_MEMMOVE) && !defined(memmove)
 791 #define memmove(d, s, c)                bcopy(s, d, c)
 792 #endif
 793
 794 #ifndef PGDLLIMPORT
 795 #define PGDLLIMPORT                             /* no special DLL markers on most ports */
 796 #endif
 797
 798 /*
 799  * The following is used as the arg list for signal handlers.  Any ports
 800  * that take something other than an int argument should override this in
 801  * their pg_config_os.h file.  Note that variable names are required
 802  * because it is used in both the prototypes as well as the definitions.
 803  * Note also the long name.  We expect that this won't collide with
 804  * other names causing compiler warnings.
 805  */
 806
 807 #ifndef SIGNAL_ARGS
 808 #define SIGNAL_ARGS  int postgres_signal_arg
 809 #endif
 810
 811 /*
 812  * When there is no sigsetjmp, its functionality is provided by plain
 813  * setjmp. Incidentally, nothing provides setjmp's functionality in
 814  * that case.
 815  */
 816 #ifndef HAVE_SIGSETJMP
 817 #define sigjmp_buf jmp_buf
 818 #define sigsetjmp(x,y) setjmp(x)
 819 #define siglongjmp longjmp
 820 #endif
 821
 822 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
 823 extern int      fdatasync(int fildes);
 824 #endif
 825
 826 /* If strtoq() exists, rename it to the more standard strtoll() */
 827 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
 828 #define strtoll strtoq
 829 #define HAVE_STRTOLL 1
 830 #endif
 831
 832 /* If strtouq() exists, rename it to the more standard strtoull() */
 833 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
 834 #define strtoull strtouq
 835 #define HAVE_STRTOULL 1
 836 #endif
 837
 838 /*
 839  * We assume if we have these two functions, we have their friends too, and
 840  * can use the wide-character functions.
 841  */
 842 #if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
 843 #define USE_WIDE_UPPER_LOWER
 844 #endif
 845
 846 /* EXEC_BACKEND defines */
 847 #ifdef EXEC_BACKEND
 848 #define NON_EXEC_STATIC
 849 #else
 850 #define NON_EXEC_STATIC static
 851 #endif
 852
 853 /* /port compatibility functions */
 854 #include "port.h"
 855
 856 #endif   /* C_H */