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) 1996-2021, PostgreSQL Global Development Group
  13  * Portions Copyright (c) 1994, Regents of the University of California
  14  *
  15  * src/include/c.h
  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)              compiler characteristics
  30  *              2)              bool, true, false
  31  *              3)              standard system types
  32  *              4)              IsValid macros for system types
  33  *              5)              offsetof, lengthof, alignment
  34  *              6)              assertions
  35  *              7)              widely useful macros
  36  *              8)              random stuff
  37  *              9)              system-specific hacks
  38  *
  39  * NOTE: since this file is included by both frontend and backend modules,
  40  * it's usually wrong to put an "extern" declaration here, unless it's
  41  * ifdef'd so that it's seen in only one case or the other.
  42  * typedefs and macros are the kind of thing that might go here.
  43  *
  44  *----------------------------------------------------------------
  45  */
  46 #ifndef C_H
  47 #define C_H
  48
  49 #include "postgres_ext.h"
  50
  51 /* Must undef pg_config_ext.h symbols before including pg_config.h */
  52 #undef PG_INT64_TYPE
  53
  54 #include "pg_config.h"
  55 #include "pg_config_manual.h"   /* must be after pg_config.h */
  56 #include "pg_config_os.h"               /* must be before any system header files */
  57
  58 /* System header files that should be available everywhere in Postgres */
  59 #include <stdio.h>
  60 #include <stdlib.h>
  61 #include <string.h>
  62 #include <stddef.h>
  63 #include <stdarg.h>
  64 #ifdef HAVE_STRINGS_H
  65 #include <strings.h>
  66 #endif
  67 #include <stdint.h>
  68 #include <sys/types.h>
  69 #include <errno.h>
  70 #if defined(WIN32) || defined(__CYGWIN__)
  71 #include <fcntl.h>                              /* ensure O_BINARY is available */
  72 #endif
  73 #include <locale.h>
  74 #ifdef ENABLE_NLS
  75 #include <libintl.h>
  76 #endif
  77
  78
  79 /* ----------------------------------------------------------------
  80  *                              Section 1: compiler characteristics
  81  *
  82  * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
  83  * ----------------------------------------------------------------
  84  */
  85
  86 /*
  87  * Disable "inline" if PG_FORCE_DISABLE_INLINE is defined.
  88  * This is used to work around compiler bugs and might also be useful for
  89  * investigatory purposes.
  90  */
  91 #ifdef PG_FORCE_DISABLE_INLINE
  92 #undef inline
  93 #define inline
  94 #endif
  95
  96 /*
  97  * Attribute macros
  98  *
  99  * GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
 100  * GCC: https://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html
 101  * Clang: https://clang.llvm.org/docs/AttributeReference.html
 102  * Sunpro: https://docs.oracle.com/cd/E18659_01/html/821-1384/gjzke.html
 103  * XLC: https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.2/com.ibm.xlc131.aix.doc/language_ref/function_attributes.html
 104  * XLC: https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.2/com.ibm.xlc131.aix.doc/language_ref/type_attrib.html
 105  */
 106
 107 /*
 108  * For compilers which don't support __has_attribute, we just define
 109  * __has_attribute(x) to 0 so that we can define macros for various
 110  * __attribute__s more easily below.
 111  */
 112 #ifndef __has_attribute
 113 #define __has_attribute(attribute) 0
 114 #endif
 115
 116 /* only GCC supports the unused attribute */
 117 #ifdef __GNUC__
 118 #define pg_attribute_unused() __attribute__((unused))
 119 #else
 120 #define pg_attribute_unused()
 121 #endif
 122
 123 /*
 124  * pg_nodiscard means the compiler should warn if the result of a function
 125  * call is ignored.  The name "nodiscard" is chosen in alignment with
 126  * (possibly future) C and C++ standards.  For maximum compatibility, use it
 127  * as a function declaration specifier, so it goes before the return type.
 128  */
 129 #ifdef __GNUC__
 130 #define pg_nodiscard __attribute__((warn_unused_result))
 131 #else
 132 #define pg_nodiscard
 133 #endif
 134
 135 /*
 136  * Place this macro before functions that should be allowed to make misaligned
 137  * accesses.  Think twice before using it on non-x86-specific code!
 138  * Testing can be done with "-fsanitize=alignment -fsanitize-trap=alignment"
 139  * on clang, or "-fsanitize=alignment -fno-sanitize-recover=alignment" on gcc.
 140  */
 141 #if __clang_major__ >= 7 || __GNUC__ >= 8
 142 #define pg_attribute_no_sanitize_alignment() __attribute__((no_sanitize("alignment")))
 143 #else
 144 #define pg_attribute_no_sanitize_alignment()
 145 #endif
 146
 147 /*
 148  * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
 149  * used in assert-enabled builds, to avoid compiler warnings about unused
 150  * variables in assert-disabled builds.
 151  */
 152 #ifdef USE_ASSERT_CHECKING
 153 #define PG_USED_FOR_ASSERTS_ONLY
 154 #else
 155 #define PG_USED_FOR_ASSERTS_ONLY pg_attribute_unused()
 156 #endif
 157
 158 /* GCC and XLC support format attributes */
 159 #if defined(__GNUC__) || defined(__IBMC__)
 160 #define pg_attribute_format_arg(a) __attribute__((format_arg(a)))
 161 #define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a)))
 162 #else
 163 #define pg_attribute_format_arg(a)
 164 #define pg_attribute_printf(f,a)
 165 #endif
 166
 167 /* GCC, Sunpro and XLC support aligned, packed and noreturn */
 168 #if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
 169 #define pg_attribute_aligned(a) __attribute__((aligned(a)))
 170 #define pg_attribute_noreturn() __attribute__((noreturn))
 171 #define pg_attribute_packed() __attribute__((packed))
 172 #define HAVE_PG_ATTRIBUTE_NORETURN 1
 173 #else
 174 /*
 175  * NB: aligned and packed are not given default definitions because they
 176  * affect code functionality; they *must* be implemented by the compiler
 177  * if they are to be used.
 178  */
 179 #define pg_attribute_noreturn()
 180 #endif
 181
 182 /*
 183  * Use "pg_attribute_always_inline" in place of "inline" for functions that
 184  * we wish to force inlining of, even when the compiler's heuristics would
 185  * choose not to.  But, if possible, don't force inlining in unoptimized
 186  * debug builds.
 187  */
 188 #if (defined(__GNUC__) && __GNUC__ > 3 && defined(__OPTIMIZE__)) || defined(__SUNPRO_C) || defined(__IBMC__)
 189 /* GCC > 3, Sunpro and XLC support always_inline via __attribute__ */
 190 #define pg_attribute_always_inline __attribute__((always_inline)) inline
 191 #elif defined(_MSC_VER)
 192 /* MSVC has a special keyword for this */
 193 #define pg_attribute_always_inline __forceinline
 194 #else
 195 /* Otherwise, the best we can do is to say "inline" */
 196 #define pg_attribute_always_inline inline
 197 #endif
 198
 199 /*
 200  * Forcing a function not to be inlined can be useful if it's the slow path of
 201  * a performance-critical function, or should be visible in profiles to allow
 202  * for proper cost attribution.  Note that unlike the pg_attribute_XXX macros
 203  * above, this should be placed before the function's return type and name.
 204  */
 205 /* GCC, Sunpro and XLC support noinline via __attribute__ */
 206 #if (defined(__GNUC__) && __GNUC__ > 2) || defined(__SUNPRO_C) || defined(__IBMC__)
 207 #define pg_noinline __attribute__((noinline))
 208 /* msvc via declspec */
 209 #elif defined(_MSC_VER)
 210 #define pg_noinline __declspec(noinline)
 211 #else
 212 #define pg_noinline
 213 #endif
 214
 215 /*
 216  * For now, just define pg_attribute_cold and pg_attribute_hot to be empty
 217  * macros on minGW 8.1.  There appears to be a compiler bug that results in
 218  * compilation failure.  At this time, we still have at least one buildfarm
 219  * animal running that compiler, so this should make that green again. It's
 220  * likely this compiler is not popular enough to warrant keeping this code
 221  * around forever, so let's just remove it once the last buildfarm animal
 222  * upgrades.
 223  */
 224 #if defined(__MINGW64__) && __GNUC__ == 8 && __GNUC_MINOR__ == 1
 225
 226 #define pg_attribute_cold
 227 #define pg_attribute_hot
 228
 229 #else
 230 /*
 231  * Marking certain functions as "hot" or "cold" can be useful to assist the
 232  * compiler in arranging the assembly code in a more efficient way.
 233  */
 234 #if __has_attribute (cold)
 235 #define pg_attribute_cold __attribute__((cold))
 236 #else
 237 #define pg_attribute_cold
 238 #endif
 239
 240 #if __has_attribute (hot)
 241 #define pg_attribute_hot __attribute__((hot))
 242 #else
 243 #define pg_attribute_hot
 244 #endif
 245
 246 #endif                                                  /* defined(__MINGW64__) && __GNUC__ == 8 &&
 247                                                                  * __GNUC_MINOR__ == 1 */
 248 /*
 249  * Mark a point as unreachable in a portable fashion.  This should preferably
 250  * be something that the compiler understands, to aid code generation.
 251  * In assert-enabled builds, we prefer abort() for debugging reasons.
 252  */
 253 #if defined(HAVE__BUILTIN_UNREACHABLE) && !defined(USE_ASSERT_CHECKING)
 254 #define pg_unreachable() __builtin_unreachable()
 255 #elif defined(_MSC_VER) && !defined(USE_ASSERT_CHECKING)
 256 #define pg_unreachable() __assume(0)
 257 #else
 258 #define pg_unreachable() abort()
 259 #endif
 260
 261 /*
 262  * Hints to the compiler about the likelihood of a branch. Both likely() and
 263  * unlikely() return the boolean value of the contained expression.
 264  *
 265  * These should only be used sparingly, in very hot code paths. It's very easy
 266  * to mis-estimate likelihoods.
 267  */
 268 #if __GNUC__ >= 3
 269 #define likely(x)       __builtin_expect((x) != 0, 1)
 270 #define unlikely(x) __builtin_expect((x) != 0, 0)
 271 #else
 272 #define likely(x)       ((x) != 0)
 273 #define unlikely(x) ((x) != 0)
 274 #endif
 275
 276 /*
 277  * CppAsString
 278  *              Convert the argument to a string, using the C preprocessor.
 279  * CppAsString2
 280  *              Convert the argument to a string, after one round of macro expansion.
 281  * CppConcat
 282  *              Concatenate two arguments together, using the C preprocessor.
 283  *
 284  * Note: There used to be support here for pre-ANSI C compilers that didn't
 285  * support # and ##.  Nowadays, these macros are just for clarity and/or
 286  * backward compatibility with existing PostgreSQL code.
 287  */
 288 #define CppAsString(identifier) #identifier
 289 #define CppAsString2(x)                 CppAsString(x)
 290 #define CppConcat(x, y)                 x##y
 291
 292 /*
 293  * VA_ARGS_NARGS
 294  *              Returns the number of macro arguments it is passed.
 295  *
 296  * An empty argument still counts as an argument, so effectively, this is
 297  * "one more than the number of commas in the argument list".
 298  *
 299  * This works for up to 63 arguments.  Internally, VA_ARGS_NARGS_() is passed
 300  * 64+N arguments, and the C99 standard only requires macros to allow up to
 301  * 127 arguments, so we can't portably go higher.  The implementation is
 302  * pretty trivial: VA_ARGS_NARGS_() returns its 64th argument, and we set up
 303  * the call so that that is the appropriate one of the list of constants.
 304  * This idea is due to Laurent Deniau.
 305  */
 306 #define VA_ARGS_NARGS(...) \
 307         VA_ARGS_NARGS_(__VA_ARGS__, \
 308                                    63,62,61,60,                   \
 309                                    59,58,57,56,55,54,53,52,51,50, \
 310                                    49,48,47,46,45,44,43,42,41,40, \
 311                                    39,38,37,36,35,34,33,32,31,30, \
 312                                    29,28,27,26,25,24,23,22,21,20, \
 313                                    19,18,17,16,15,14,13,12,11,10, \
 314                                    9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
 315 #define VA_ARGS_NARGS_( \
 316         _01,_02,_03,_04,_05,_06,_07,_08,_09,_10, \
 317         _11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
 318         _21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
 319         _31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
 320         _41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
 321         _51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
 322         _61,_62,_63,  N, ...) \
 323         (N)
 324
 325 /*
 326  * dummyret is used to set return values in macros that use ?: to make
 327  * assignments.  gcc wants these to be void, other compilers like char
 328  */
 329 #ifdef __GNUC__                                 /* GNU cc */
 330 #define dummyret        void
 331 #else
 332 #define dummyret        char
 333 #endif
 334
 335 /*
 336  * Generic function pointer.  This can be used in the rare cases where it's
 337  * necessary to cast a function pointer to a seemingly incompatible function
 338  * pointer type while avoiding gcc's -Wcast-function-type warnings.
 339  */
 340 typedef void (*pg_funcptr_t) (void);
 341
 342 /*
 343  * We require C99, hence the compiler should understand flexible array
 344  * members.  However, for documentation purposes we still consider it to be
 345  * project style to write "field[FLEXIBLE_ARRAY_MEMBER]" not just "field[]".
 346  * When computing the size of such an object, use "offsetof(struct s, f)"
 347  * for portability.  Don't use "offsetof(struct s, f[0])", as this doesn't
 348  * work with MSVC and with C++ compilers.
 349  */
 350 #define FLEXIBLE_ARRAY_MEMBER   /* empty */
 351
 352 /* Which __func__ symbol do we have, if any? */
 353 #ifdef HAVE_FUNCNAME__FUNC
 354 #define PG_FUNCNAME_MACRO       __func__
 355 #else
 356 #ifdef HAVE_FUNCNAME__FUNCTION
 357 #define PG_FUNCNAME_MACRO       __FUNCTION__
 358 #else
 359 #define PG_FUNCNAME_MACRO       NULL
 360 #endif
 361 #endif
 362
 363
 364 /* ----------------------------------------------------------------
 365  *                              Section 2:      bool, true, false
 366  * ----------------------------------------------------------------
 367  */
 368
 369 /*
 370  * bool
 371  *              Boolean value, either true or false.
 372  *
 373  * We use stdbool.h if available and its bool has size 1.  That's useful for
 374  * better compiler and debugger output and for compatibility with third-party
 375  * libraries.  But PostgreSQL currently cannot deal with bool of other sizes;
 376  * there are static assertions around the code to prevent that.
 377  *
 378  * For C++ compilers, we assume the compiler has a compatible built-in
 379  * definition of bool.
 380  *
 381  * See also the version of this code in src/interfaces/ecpg/include/ecpglib.h.
 382  */
 383
 384 #ifndef __cplusplus
 385
 386 #ifdef PG_USE_STDBOOL
 387 #include <stdbool.h>
 388 #else
 389
 390 #ifndef bool
 391 typedef unsigned char bool;
 392 #endif
 393
 394 #ifndef true
 395 #define true    ((bool) 1)
 396 #endif
 397
 398 #ifndef false
 399 #define false   ((bool) 0)
 400 #endif
 401
 402 #endif                                                  /* not PG_USE_STDBOOL */
 403 #endif                                                  /* not C++ */
 404
 405
 406 /* ----------------------------------------------------------------
 407  *                              Section 3:      standard system types
 408  * ----------------------------------------------------------------
 409  */
 410
 411 /*
 412  * Pointer
 413  *              Variable holding address of any memory resident object.
 414  *
 415  *              XXX Pointer arithmetic is done with this, so it can't be void *
 416  *              under "true" ANSI compilers.
 417  */
 418 typedef char *Pointer;
 419
 420 /*
 421  * intN
 422  *              Signed integer, EXACTLY N BITS IN SIZE,
 423  *              used for numerical computations and the
 424  *              frontend/backend protocol.
 425  */
 426 #ifndef HAVE_INT8
 427 typedef signed char int8;               /* == 8 bits */
 428 typedef signed short int16;             /* == 16 bits */
 429 typedef signed int int32;               /* == 32 bits */
 430 #endif                                                  /* not HAVE_INT8 */
 431
 432 /*
 433  * uintN
 434  *              Unsigned integer, EXACTLY N BITS IN SIZE,
 435  *              used for numerical computations and the
 436  *              frontend/backend protocol.
 437  */
 438 #ifndef HAVE_UINT8
 439 typedef unsigned char uint8;    /* == 8 bits */
 440 typedef unsigned short uint16;  /* == 16 bits */
 441 typedef unsigned int uint32;    /* == 32 bits */
 442 #endif                                                  /* not HAVE_UINT8 */
 443
 444 /*
 445  * bitsN
 446  *              Unit of bitwise operation, AT LEAST N BITS IN SIZE.
 447  */
 448 typedef uint8 bits8;                    /* >= 8 bits */
 449 typedef uint16 bits16;                  /* >= 16 bits */
 450 typedef uint32 bits32;                  /* >= 32 bits */
 451
 452 /*
 453  * 64-bit integers
 454  */
 455 #ifdef HAVE_LONG_INT_64
 456 /* Plain "long int" fits, use it */
 457
 458 #ifndef HAVE_INT64
 459 typedef long int int64;
 460 #endif
 461 #ifndef HAVE_UINT64
 462 typedef unsigned long int uint64;
 463 #endif
 464 #define INT64CONST(x)  (x##L)
 465 #define UINT64CONST(x) (x##UL)
 466 #elif defined(HAVE_LONG_LONG_INT_64)
 467 /* We have working support for "long long int", use that */
 468
 469 #ifndef HAVE_INT64
 470 typedef long long int int64;
 471 #endif
 472 #ifndef HAVE_UINT64
 473 typedef unsigned long long int uint64;
 474 #endif
 475 #define INT64CONST(x)  (x##LL)
 476 #define UINT64CONST(x) (x##ULL)
 477 #else
 478 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
 479 #error must have a working 64-bit integer datatype
 480 #endif
 481
 482 /* snprintf format strings to use for 64-bit integers */
 483 #define INT64_FORMAT "%" INT64_MODIFIER "d"
 484 #define UINT64_FORMAT "%" INT64_MODIFIER "u"
 485
 486 /*
 487  * 128-bit signed and unsigned integers
 488  *              There currently is only limited support for such types.
 489  *              E.g. 128bit literals and snprintf are not supported; but math is.
 490  *              Also, because we exclude such types when choosing MAXIMUM_ALIGNOF,
 491  *              it must be possible to coerce the compiler to allocate them on no
 492  *              more than MAXALIGN boundaries.
 493  */
 494 #if defined(PG_INT128_TYPE)
 495 #if defined(pg_attribute_aligned) || ALIGNOF_PG_INT128_TYPE <= MAXIMUM_ALIGNOF
 496 #define HAVE_INT128 1
 497
 498 typedef PG_INT128_TYPE int128
 499 #if defined(pg_attribute_aligned)
 500                         pg_attribute_aligned(MAXIMUM_ALIGNOF)
 501 #endif
 502                    ;
 503
 504 typedef unsigned PG_INT128_TYPE uint128
 505 #if defined(pg_attribute_aligned)
 506                         pg_attribute_aligned(MAXIMUM_ALIGNOF)
 507 #endif
 508                    ;
 509
 510 #endif
 511 #endif
 512
 513 /*
 514  * stdint.h limits aren't guaranteed to have compatible types with our fixed
 515  * width types. So just define our own.
 516  */
 517 #define PG_INT8_MIN             (-0x7F-1)
 518 #define PG_INT8_MAX             (0x7F)
 519 #define PG_UINT8_MAX    (0xFF)
 520 #define PG_INT16_MIN    (-0x7FFF-1)
 521 #define PG_INT16_MAX    (0x7FFF)
 522 #define PG_UINT16_MAX   (0xFFFF)
 523 #define PG_INT32_MIN    (-0x7FFFFFFF-1)
 524 #define PG_INT32_MAX    (0x7FFFFFFF)
 525 #define PG_UINT32_MAX   (0xFFFFFFFFU)
 526 #define PG_INT64_MIN    (-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
 527 #define PG_INT64_MAX    INT64CONST(0x7FFFFFFFFFFFFFFF)
 528 #define PG_UINT64_MAX   UINT64CONST(0xFFFFFFFFFFFFFFFF)
 529
 530 /*
 531  * We now always use int64 timestamps, but keep this symbol defined for the
 532  * benefit of external code that might test it.
 533  */
 534 #define HAVE_INT64_TIMESTAMP
 535
 536 /*
 537  * Size
 538  *              Size of any memory resident object, as returned by sizeof.
 539  */
 540 typedef size_t Size;
 541
 542 /*
 543  * Index
 544  *              Index into any memory resident array.
 545  *
 546  * Note:
 547  *              Indices are non negative.
 548  */
 549 typedef unsigned int Index;
 550
 551 /*
 552  * Offset
 553  *              Offset into any memory resident array.
 554  *
 555  * Note:
 556  *              This differs from an Index in that an Index is always
 557  *              non negative, whereas Offset may be negative.
 558  */
 559 typedef signed int Offset;
 560
 561 /*
 562  * Common Postgres datatype names (as used in the catalogs)
 563  */
 564 typedef float float4;
 565 typedef double float8;
 566
 567 #ifdef USE_FLOAT8_BYVAL
 568 #define FLOAT8PASSBYVAL true
 569 #else
 570 #define FLOAT8PASSBYVAL false
 571 #endif
 572
 573 /*
 574  * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
 575  * CommandId
 576  */
 577
 578 /* typedef Oid is in postgres_ext.h */
 579
 580 /*
 581  * regproc is the type name used in the include/catalog headers, but
 582  * RegProcedure is the preferred name in C code.
 583  */
 584 typedef Oid regproc;
 585 typedef regproc RegProcedure;
 586
 587 typedef uint32 TransactionId;
 588
 589 typedef uint32 LocalTransactionId;
 590
 591 typedef uint32 SubTransactionId;
 592
 593 #define InvalidSubTransactionId         ((SubTransactionId) 0)
 594 #define TopSubTransactionId                     ((SubTransactionId) 1)
 595
 596 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
 597 typedef TransactionId MultiXactId;
 598
 599 typedef uint32 MultiXactOffset;
 600
 601 typedef uint32 CommandId;
 602
 603 #define FirstCommandId  ((CommandId) 0)
 604 #define InvalidCommandId        (~(CommandId)0)
 605
 606
 607 /* ----------------
 608  *              Variable-length datatypes all share the 'struct varlena' header.
 609  *
 610  * NOTE: for TOASTable types, this is an oversimplification, since the value
 611  * may be compressed or moved out-of-line.  However datatype-specific routines
 612  * are mostly content to deal with de-TOASTed values only, and of course
 613  * client-side routines should never see a TOASTed value.  But even in a
 614  * de-TOASTed value, beware of touching vl_len_ directly, as its
 615  * representation is no longer convenient.  It's recommended that code always
 616  * use macros VARDATA_ANY, VARSIZE_ANY, VARSIZE_ANY_EXHDR, VARDATA, VARSIZE,
 617  * and SET_VARSIZE instead of relying on direct mentions of the struct fields.
 618  * See postgres.h for details of the TOASTed form.
 619  * ----------------
 620  */
 621 struct varlena
 622 {
 623         char            vl_len_[4];             /* Do not touch this field directly! */
 624         char            vl_dat[FLEXIBLE_ARRAY_MEMBER];  /* Data content is here */
 625 };
 626
 627 #define VARHDRSZ                ((int32) sizeof(int32))
 628
 629 /*
 630  * These widely-used datatypes are just a varlena header and the data bytes.
 631  * There is no terminating null or anything like that --- the data length is
 632  * always VARSIZE_ANY_EXHDR(ptr).
 633  */
 634 typedef struct varlena bytea;
 635 typedef struct varlena text;
 636 typedef struct varlena BpChar;  /* blank-padded char, ie SQL char(n) */
 637 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
 638
 639 /*
 640  * Specialized array types.  These are physically laid out just the same
 641  * as regular arrays (so that the regular array subscripting code works
 642  * with them).  They exist as distinct types mostly for historical reasons:
 643  * they have nonstandard I/O behavior which we don't want to change for fear
 644  * of breaking applications that look at the system catalogs.  There is also
 645  * an implementation issue for oidvector: it's part of the primary key for
 646  * pg_proc, and we can't use the normal btree array support routines for that
 647  * without circularity.
 648  */
 649 typedef struct
 650 {
 651         int32           vl_len_;                /* these fields must match ArrayType! */
 652         int                     ndim;                   /* always 1 for int2vector */
 653         int32           dataoffset;             /* always 0 for int2vector */
 654         Oid                     elemtype;
 655         int                     dim1;
 656         int                     lbound1;
 657         int16           values[FLEXIBLE_ARRAY_MEMBER];
 658 } int2vector;
 659
 660 typedef struct
 661 {
 662         int32           vl_len_;                /* these fields must match ArrayType! */
 663         int                     ndim;                   /* always 1 for oidvector */
 664         int32           dataoffset;             /* always 0 for oidvector */
 665         Oid                     elemtype;
 666         int                     dim1;
 667         int                     lbound1;
 668         Oid                     values[FLEXIBLE_ARRAY_MEMBER];
 669 } oidvector;
 670
 671 /*
 672  * Representation of a Name: effectively just a C string, but null-padded to
 673  * exactly NAMEDATALEN bytes.  The use of a struct is historical.
 674  */
 675 typedef struct nameData
 676 {
 677         char            data[NAMEDATALEN];
 678 } NameData;
 679 typedef NameData *Name;
 680
 681 #define NameStr(name)   ((name).data)
 682
 683
 684 /* ----------------------------------------------------------------
 685  *                              Section 4:      IsValid macros for system types
 686  * ----------------------------------------------------------------
 687  */
 688 /*
 689  * BoolIsValid
 690  *              True iff bool is valid.
 691  */
 692 #define BoolIsValid(boolean)    ((boolean) == false || (boolean) == true)
 693
 694 /*
 695  * PointerIsValid
 696  *              True iff pointer is valid.
 697  */
 698 #define PointerIsValid(pointer) ((const void*)(pointer) != NULL)
 699
 700 /*
 701  * PointerIsAligned
 702  *              True iff pointer is properly aligned to point to the given type.
 703  */
 704 #define PointerIsAligned(pointer, type) \
 705                 (((uintptr_t)(pointer) % (sizeof (type))) == 0)
 706
 707 #define OffsetToPointer(base, offset) \
 708                 ((void *)((char *) base + offset))
 709
 710 #define OidIsValid(objectId)  ((bool) ((objectId) != InvalidOid))
 711
 712 #define RegProcedureIsValid(p)  OidIsValid(p)
 713
 714
 715 /* ----------------------------------------------------------------
 716  *                              Section 5:      offsetof, lengthof, alignment
 717  * ----------------------------------------------------------------
 718  */
 719 /*
 720  * offsetof
 721  *              Offset of a structure/union field within that structure/union.
 722  *
 723  *              XXX This is supposed to be part of stddef.h, but isn't on
 724  *              some systems (like SunOS 4).
 725  */
 726 #ifndef offsetof
 727 #define offsetof(type, field)   ((long) &((type *)0)->field)
 728 #endif                                                  /* offsetof */
 729
 730 /*
 731  * lengthof
 732  *              Number of elements in an array.
 733  */
 734 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
 735
 736 /* ----------------
 737  * Alignment macros: align a length or address appropriately for a given type.
 738  * The fooALIGN() macros round up to a multiple of the required alignment,
 739  * while the fooALIGN_DOWN() macros round down.  The latter are more useful
 740  * for problems like "how many X-sized structures will fit in a page?".
 741  *
 742  * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
 743  * That case seems extremely unlikely to be needed in practice, however.
 744  *
 745  * NOTE: MAXIMUM_ALIGNOF, and hence MAXALIGN(), intentionally exclude any
 746  * larger-than-8-byte types the compiler might have.
 747  * ----------------
 748  */
 749
 750 #define TYPEALIGN(ALIGNVAL,LEN)  \
 751         (((uintptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((uintptr_t) ((ALIGNVAL) - 1)))
 752
 753 #define SHORTALIGN(LEN)                 TYPEALIGN(ALIGNOF_SHORT, (LEN))
 754 #define INTALIGN(LEN)                   TYPEALIGN(ALIGNOF_INT, (LEN))
 755 #define LONGALIGN(LEN)                  TYPEALIGN(ALIGNOF_LONG, (LEN))
 756 #define DOUBLEALIGN(LEN)                TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
 757 #define MAXALIGN(LEN)                   TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
 758 /* MAXALIGN covers only built-in types, not buffers */
 759 #define BUFFERALIGN(LEN)                TYPEALIGN(ALIGNOF_BUFFER, (LEN))
 760 #define CACHELINEALIGN(LEN)             TYPEALIGN(PG_CACHE_LINE_SIZE, (LEN))
 761
 762 #define TYPEALIGN_DOWN(ALIGNVAL,LEN)  \
 763         (((uintptr_t) (LEN)) & ~((uintptr_t) ((ALIGNVAL) - 1)))
 764
 765 #define SHORTALIGN_DOWN(LEN)    TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
 766 #define INTALIGN_DOWN(LEN)              TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
 767 #define LONGALIGN_DOWN(LEN)             TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
 768 #define DOUBLEALIGN_DOWN(LEN)   TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
 769 #define MAXALIGN_DOWN(LEN)              TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
 770 #define BUFFERALIGN_DOWN(LEN)   TYPEALIGN_DOWN(ALIGNOF_BUFFER, (LEN))
 771
 772 /*
 773  * The above macros will not work with types wider than uintptr_t, like with
 774  * uint64 on 32-bit platforms.  That's not problem for the usual use where a
 775  * pointer or a length is aligned, but for the odd case that you need to
 776  * align something (potentially) wider, use TYPEALIGN64.
 777  */
 778 #define TYPEALIGN64(ALIGNVAL,LEN)  \
 779         (((uint64) (LEN) + ((ALIGNVAL) - 1)) & ~((uint64) ((ALIGNVAL) - 1)))
 780
 781 /* we don't currently need wider versions of the other ALIGN macros */
 782 #define MAXALIGN64(LEN)                 TYPEALIGN64(MAXIMUM_ALIGNOF, (LEN))
 783
 784
 785 /* ----------------------------------------------------------------
 786  *                              Section 6:      assertions
 787  * ----------------------------------------------------------------
 788  */
 789
 790 /*
 791  * USE_ASSERT_CHECKING, if defined, turns on all the assertions.
 792  * - plai  9/5/90
 793  *
 794  * It should _NOT_ be defined in releases or in benchmark copies
 795  */
 796
 797 /*
 798  * Assert() can be used in both frontend and backend code. In frontend code it
 799  * just calls the standard assert, if it's available. If use of assertions is
 800  * not configured, it does nothing.
 801  */
 802 #ifndef USE_ASSERT_CHECKING
 803
 804 #define Assert(condition)       ((void)true)
 805 #define AssertMacro(condition)  ((void)true)
 806 #define AssertArg(condition)    ((void)true)
 807 #define AssertState(condition)  ((void)true)
 808 #define AssertPointerAlignment(ptr, bndr)       ((void)true)
 809 #define Trap(condition, errorType)      ((void)true)
 810 #define TrapMacro(condition, errorType) (true)
 811
 812 #elif defined(FRONTEND)
 813
 814 #include <assert.h>
 815 #define Assert(p) assert(p)
 816 #define AssertMacro(p)  ((void) assert(p))
 817 #define AssertArg(condition) assert(condition)
 818 #define AssertState(condition) assert(condition)
 819 #define AssertPointerAlignment(ptr, bndr)       ((void)true)
 820
 821 #else                                                   /* USE_ASSERT_CHECKING && !FRONTEND */
 822
 823 /*
 824  * Trap
 825  *              Generates an exception if the given condition is true.
 826  */
 827 #define Trap(condition, errorType) \
 828         do { \
 829                 if (condition) \
 830                         ExceptionalCondition(#condition, (errorType), \
 831                                                                  __FILE__, __LINE__); \
 832         } while (0)
 833
 834 /*
 835  *      TrapMacro is the same as Trap but it's intended for use in macros:
 836  *
 837  *              #define foo(x) (AssertMacro(x != 0), bar(x))
 838  *
 839  *      Isn't CPP fun?
 840  */
 841 #define TrapMacro(condition, errorType) \
 842         ((bool) (! (condition) || \
 843                          (ExceptionalCondition(#condition, (errorType), \
 844                                                                    __FILE__, __LINE__), 0)))
 845
 846 #define Assert(condition) \
 847         do { \
 848                 if (!(condition)) \
 849                         ExceptionalCondition(#condition, "FailedAssertion", \
 850                                                                  __FILE__, __LINE__); \
 851         } while (0)
 852
 853 #define AssertMacro(condition) \
 854         ((void) ((condition) || \
 855                          (ExceptionalCondition(#condition, "FailedAssertion", \
 856                                                                    __FILE__, __LINE__), 0)))
 857
 858 #define AssertArg(condition) \
 859         do { \
 860                 if (!(condition)) \
 861                         ExceptionalCondition(#condition, "BadArgument", \
 862                                                                  __FILE__, __LINE__); \
 863         } while (0)
 864
 865 #define AssertState(condition) \
 866         do { \
 867                 if (!(condition)) \
 868                         ExceptionalCondition(#condition, "BadState", \
 869                                                                  __FILE__, __LINE__); \
 870         } while (0)
 871
 872 /*
 873  * Check that `ptr' is `bndr' aligned.
 874  */
 875 #define AssertPointerAlignment(ptr, bndr) \
 876         Trap(TYPEALIGN(bndr, (uintptr_t)(ptr)) != (uintptr_t)(ptr), \
 877                  "UnalignedPointer")
 878
 879 #endif                                                  /* USE_ASSERT_CHECKING && !FRONTEND */
 880
 881 /*
 882  * ExceptionalCondition is compiled into the backend whether or not
 883  * USE_ASSERT_CHECKING is defined, so as to support use of extensions
 884  * that are built with that #define with a backend that isn't.  Hence,
 885  * we should declare it as long as !FRONTEND.
 886  */
 887 #ifndef FRONTEND
 888 extern void ExceptionalCondition(const char *conditionName,
 889                                                                  const char *errorType,
 890                                                                  const char *fileName, int lineNumber) pg_attribute_noreturn();
 891 #endif
 892
 893 /*
 894  * Macros to support compile-time assertion checks.
 895  *
 896  * If the "condition" (a compile-time-constant expression) evaluates to false,
 897  * throw a compile error using the "errmessage" (a string literal).
 898  *
 899  * gcc 4.6 and up supports _Static_assert(), but there are bizarre syntactic
 900  * placement restrictions.  Macros StaticAssertStmt() and StaticAssertExpr()
 901  * make it safe to use as a statement or in an expression, respectively.
 902  * The macro StaticAssertDecl() is suitable for use at file scope (outside of
 903  * any function).
 904  *
 905  * Otherwise we fall back on a kluge that assumes the compiler will complain
 906  * about a negative width for a struct bit-field.  This will not include a
 907  * helpful error message, but it beats not getting an error at all.
 908  */
 909 #ifndef __cplusplus
 910 #ifdef HAVE__STATIC_ASSERT
 911 #define StaticAssertStmt(condition, errmessage) \
 912         do { _Static_assert(condition, errmessage); } while(0)
 913 #define StaticAssertExpr(condition, errmessage) \
 914         ((void) ({ StaticAssertStmt(condition, errmessage); true; }))
 915 #define StaticAssertDecl(condition, errmessage) \
 916         _Static_assert(condition, errmessage)
 917 #else                                                   /* !HAVE__STATIC_ASSERT */
 918 #define StaticAssertStmt(condition, errmessage) \
 919         ((void) sizeof(struct { int static_assert_failure : (condition) ? 1 : -1; }))
 920 #define StaticAssertExpr(condition, errmessage) \
 921         StaticAssertStmt(condition, errmessage)
 922 #define StaticAssertDecl(condition, errmessage) \
 923         extern void static_assert_func(int static_assert_failure[(condition) ? 1 : -1])
 924 #endif                                                  /* HAVE__STATIC_ASSERT */
 925 #else                                                   /* C++ */
 926 #if defined(__cpp_static_assert) && __cpp_static_assert >= 200410
 927 #define StaticAssertStmt(condition, errmessage) \
 928         static_assert(condition, errmessage)
 929 #define StaticAssertExpr(condition, errmessage) \
 930         ({ static_assert(condition, errmessage); })
 931 #define StaticAssertDecl(condition, errmessage) \
 932         static_assert(condition, errmessage)
 933 #else                                                   /* !__cpp_static_assert */
 934 #define StaticAssertStmt(condition, errmessage) \
 935         do { struct static_assert_struct { int static_assert_failure : (condition) ? 1 : -1; }; } while(0)
 936 #define StaticAssertExpr(condition, errmessage) \
 937         ((void) ({ StaticAssertStmt(condition, errmessage); }))
 938 #define StaticAssertDecl(condition, errmessage) \
 939         extern void static_assert_func(int static_assert_failure[(condition) ? 1 : -1])
 940 #endif                                                  /* __cpp_static_assert */
 941 #endif                                                  /* C++ */
 942
 943
 944 /*
 945  * Compile-time checks that a variable (or expression) has the specified type.
 946  *
 947  * AssertVariableIsOfType() can be used as a statement.
 948  * AssertVariableIsOfTypeMacro() is intended for use in macros, eg
 949  *              #define foo(x) (AssertVariableIsOfTypeMacro(x, int), bar(x))
 950  *
 951  * If we don't have __builtin_types_compatible_p, we can still assert that
 952  * the types have the same size.  This is far from ideal (especially on 32-bit
 953  * platforms) but it provides at least some coverage.
 954  */
 955 #ifdef HAVE__BUILTIN_TYPES_COMPATIBLE_P
 956 #define AssertVariableIsOfType(varname, typename) \
 957         StaticAssertStmt(__builtin_types_compatible_p(__typeof__(varname), typename), \
 958         CppAsString(varname) " does not have type " CppAsString(typename))
 959 #define AssertVariableIsOfTypeMacro(varname, typename) \
 960         (StaticAssertExpr(__builtin_types_compatible_p(__typeof__(varname), typename), \
 961          CppAsString(varname) " does not have type " CppAsString(typename)))
 962 #else                                                   /* !HAVE__BUILTIN_TYPES_COMPATIBLE_P */
 963 #define AssertVariableIsOfType(varname, typename) \
 964         StaticAssertStmt(sizeof(varname) == sizeof(typename), \
 965         CppAsString(varname) " does not have type " CppAsString(typename))
 966 #define AssertVariableIsOfTypeMacro(varname, typename) \
 967         (StaticAssertExpr(sizeof(varname) == sizeof(typename), \
 968          CppAsString(varname) " does not have type " CppAsString(typename)))
 969 #endif                                                  /* HAVE__BUILTIN_TYPES_COMPATIBLE_P */
 970
 971
 972 /* ----------------------------------------------------------------
 973  *                              Section 7:      widely useful macros
 974  * ----------------------------------------------------------------
 975  */
 976 /*
 977  * Max
 978  *              Return the maximum of two numbers.
 979  */
 980 #define Max(x, y)               ((x) > (y) ? (x) : (y))
 981
 982 /*
 983  * Min
 984  *              Return the minimum of two numbers.
 985  */
 986 #define Min(x, y)               ((x) < (y) ? (x) : (y))
 987
 988 /*
 989  * Abs
 990  *              Return the absolute value of the argument.
 991  */
 992 #define Abs(x)                  ((x) >= 0 ? (x) : -(x))
 993
 994
 995 /* Get a bit mask of the bits set in non-long aligned addresses */
 996 #define LONG_ALIGN_MASK (sizeof(long) - 1)
 997
 998 /*
 999  * MemSet
1000  *      Exactly the same as standard library function memset(), but considerably
1001  *      faster for zeroing small word-aligned structures (such as parsetree nodes).
1002  *      This has to be a macro because the main point is to avoid function-call
1003  *      overhead.   However, we have also found that the loop is faster than
1004  *      native libc memset() on some platforms, even those with assembler
1005  *      memset() functions.  More research needs to be done, perhaps with
1006  *      MEMSET_LOOP_LIMIT tests in configure.
1007  */
1008 #define MemSet(start, val, len) \
1009         do \
1010         { \
1011                 /* must be void* because we don't know if it is integer aligned yet */ \
1012                 void   *_vstart = (void *) (start); \
1013                 int             _val = (val); \
1014                 Size    _len = (len); \
1015 \
1016                 if ((((uintptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
1017                         (_len & LONG_ALIGN_MASK) == 0 && \
1018                         _val == 0 && \
1019                         _len <= MEMSET_LOOP_LIMIT && \
1020                         /* \
1021                          *      If MEMSET_LOOP_LIMIT == 0, optimizer should find \
1022                          *      the whole "if" false at compile time. \
1023                          */ \
1024                         MEMSET_LOOP_LIMIT != 0) \
1025                 { \
1026                         long *_start = (long *) _vstart; \
1027                         long *_stop = (long *) ((char *) _start + _len); \
1028                         while (_start < _stop) \
1029                                 *_start++ = 0; \
1030                 } \
1031                 else \
1032                         memset(_vstart, _val, _len); \
1033         } while (0)
1034
1035 /*
1036  * MemSetAligned is the same as MemSet except it omits the test to see if
1037  * "start" is word-aligned.  This is okay to use if the caller knows a-priori
1038  * that the pointer is suitably aligned (typically, because he just got it
1039  * from palloc(), which always delivers a max-aligned pointer).
1040  */
1041 #define MemSetAligned(start, val, len) \
1042         do \
1043         { \
1044                 long   *_start = (long *) (start); \
1045                 int             _val = (val); \
1046                 Size    _len = (len); \
1047 \
1048                 if ((_len & LONG_ALIGN_MASK) == 0 && \
1049                         _val == 0 && \
1050                         _len <= MEMSET_LOOP_LIMIT && \
1051                         MEMSET_LOOP_LIMIT != 0) \
1052                 { \
1053                         long *_stop = (long *) ((char *) _start + _len); \
1054                         while (_start < _stop) \
1055                                 *_start++ = 0; \
1056                 } \
1057                 else \
1058                         memset(_start, _val, _len); \
1059         } while (0)
1060
1061
1062 /*
1063  * MemSetTest/MemSetLoop are a variant version that allow all the tests in
1064  * MemSet to be done at compile time in cases where "val" and "len" are
1065  * constants *and* we know the "start" pointer must be word-aligned.
1066  * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
1067  * MemSetAligned.  Beware of multiple evaluations of the arguments when using
1068  * this approach.
1069  */
1070 #define MemSetTest(val, len) \
1071         ( ((len) & LONG_ALIGN_MASK) == 0 && \
1072         (len) <= MEMSET_LOOP_LIMIT && \
1073         MEMSET_LOOP_LIMIT != 0 && \
1074         (val) == 0 )
1075
1076 #define MemSetLoop(start, val, len) \
1077         do \
1078         { \
1079                 long * _start = (long *) (start); \
1080                 long * _stop = (long *) ((char *) _start + (Size) (len)); \
1081         \
1082                 while (_start < _stop) \
1083                         *_start++ = 0; \
1084         } while (0)
1085
1086 /*
1087  * Macros for range-checking float values before converting to integer.
1088  * We must be careful here that the boundary values are expressed exactly
1089  * in the float domain.  PG_INTnn_MIN is an exact power of 2, so it will
1090  * be represented exactly; but PG_INTnn_MAX isn't, and might get rounded
1091  * off, so avoid using that.
1092  * The input must be rounded to an integer beforehand, typically with rint(),
1093  * else we might draw the wrong conclusion about close-to-the-limit values.
1094  * These macros will do the right thing for Inf, but not necessarily for NaN,
1095  * so check isnan(num) first if that's a possibility.
1096  */
1097 #define FLOAT4_FITS_IN_INT16(num) \
1098         ((num) >= (float4) PG_INT16_MIN && (num) < -((float4) PG_INT16_MIN))
1099 #define FLOAT4_FITS_IN_INT32(num) \
1100         ((num) >= (float4) PG_INT32_MIN && (num) < -((float4) PG_INT32_MIN))
1101 #define FLOAT4_FITS_IN_INT64(num) \
1102         ((num) >= (float4) PG_INT64_MIN && (num) < -((float4) PG_INT64_MIN))
1103 #define FLOAT8_FITS_IN_INT16(num) \
1104         ((num) >= (float8) PG_INT16_MIN && (num) < -((float8) PG_INT16_MIN))
1105 #define FLOAT8_FITS_IN_INT32(num) \
1106         ((num) >= (float8) PG_INT32_MIN && (num) < -((float8) PG_INT32_MIN))
1107 #define FLOAT8_FITS_IN_INT64(num) \
1108         ((num) >= (float8) PG_INT64_MIN && (num) < -((float8) PG_INT64_MIN))
1109
1110
1111 /* ----------------------------------------------------------------
1112  *                              Section 8:      random stuff
1113  * ----------------------------------------------------------------
1114  */
1115
1116 #ifdef HAVE_STRUCT_SOCKADDR_UN
1117 #define HAVE_UNIX_SOCKETS 1
1118 #endif
1119
1120 /*
1121  * Invert the sign of a qsort-style comparison result, ie, exchange negative
1122  * and positive integer values, being careful not to get the wrong answer
1123  * for INT_MIN.  The argument should be an integral variable.
1124  */
1125 #define INVERT_COMPARE_RESULT(var) \
1126         ((var) = ((var) < 0) ? 1 : -(var))
1127
1128 /*
1129  * Use this, not "char buf[BLCKSZ]", to declare a field or local variable
1130  * holding a page buffer, if that page might be accessed as a page and not
1131  * just a string of bytes.  Otherwise the variable might be under-aligned,
1132  * causing problems on alignment-picky hardware.  (In some places, we use
1133  * this to declare buffers even though we only pass them to read() and
1134  * write(), because copying to/from aligned buffers is usually faster than
1135  * using unaligned buffers.)  We include both "double" and "int64" in the
1136  * union to ensure that the compiler knows the value must be MAXALIGN'ed
1137  * (cf. configure's computation of MAXIMUM_ALIGNOF).
1138  */
1139 typedef union PGAlignedBlock
1140 {
1141         char            data[BLCKSZ];
1142         double          force_align_d;
1143         int64           force_align_i64;
1144 } PGAlignedBlock;
1145
1146 /* Same, but for an XLOG_BLCKSZ-sized buffer */
1147 typedef union PGAlignedXLogBlock
1148 {
1149         char            data[XLOG_BLCKSZ];
1150         double          force_align_d;
1151         int64           force_align_i64;
1152 } PGAlignedXLogBlock;
1153
1154 /* msb for char */
1155 #define HIGHBIT                                 (0x80)
1156 #define IS_HIGHBIT_SET(ch)              ((unsigned char)(ch) & HIGHBIT)
1157
1158 /*
1159  * Support macros for escaping strings.  escape_backslash should be true
1160  * if generating a non-standard-conforming string.  Prefixing a string
1161  * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
1162  * Beware of multiple evaluation of the "ch" argument!
1163  */
1164 #define SQL_STR_DOUBLE(ch, escape_backslash)    \
1165         ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
1166
1167 #define ESCAPE_STRING_SYNTAX    'E'
1168
1169
1170 #define STATUS_OK                               (0)
1171 #define STATUS_ERROR                    (-1)
1172 #define STATUS_EOF                              (-2)
1173
1174 /*
1175  * gettext support
1176  */
1177
1178 #ifndef ENABLE_NLS
1179 /* stuff we'd otherwise get from <libintl.h> */
1180 #define gettext(x) (x)
1181 #define dgettext(d,x) (x)
1182 #define ngettext(s,p,n) ((n) == 1 ? (s) : (p))
1183 #define dngettext(d,s,p,n) ((n) == 1 ? (s) : (p))
1184 #endif
1185
1186 #define _(x) gettext(x)
1187
1188 /*
1189  *      Use this to mark string constants as needing translation at some later
1190  *      time, rather than immediately.  This is useful for cases where you need
1191  *      access to the original string and translated string, and for cases where
1192  *      immediate translation is not possible, like when initializing global
1193  *      variables.
1194  *
1195  *      https://www.gnu.org/software/gettext/manual/html_node/Special-cases.html
1196  */
1197 #define gettext_noop(x) (x)
1198
1199 /*
1200  * To better support parallel installations of major PostgreSQL
1201  * versions as well as parallel installations of major library soname
1202  * versions, we mangle the gettext domain name by appending those
1203  * version numbers.  The coding rule ought to be that wherever the
1204  * domain name is mentioned as a literal, it must be wrapped into
1205  * PG_TEXTDOMAIN().  The macros below do not work on non-literals; but
1206  * that is somewhat intentional because it avoids having to worry
1207  * about multiple states of premangling and postmangling as the values
1208  * are being passed around.
1209  *
1210  * Make sure this matches the installation rules in nls-global.mk.
1211  */
1212 #ifdef SO_MAJOR_VERSION
1213 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
1214 #else
1215 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
1216 #endif
1217
1218 /*
1219  * Macro that allows to cast constness and volatile away from an expression, but doesn't
1220  * allow changing the underlying type.  Enforcement of the latter
1221  * currently only works for gcc like compilers.
1222  *
1223  * Please note IT IS NOT SAFE to cast constness away if the result will ever
1224  * be modified (it would be undefined behaviour). Doing so anyway can cause
1225  * compiler misoptimizations or runtime crashes (modifying readonly memory).
1226  * It is only safe to use when the result will not be modified, but API
1227  * design or language restrictions prevent you from declaring that
1228  * (e.g. because a function returns both const and non-const variables).
1229  *
1230  * Note that this only works in function scope, not for global variables (it'd
1231  * be nice, but not trivial, to improve that).
1232  */
1233 #if defined(HAVE__BUILTIN_TYPES_COMPATIBLE_P)
1234 #define unconstify(underlying_type, expr) \
1235         (StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), const underlying_type), \
1236                                           "wrong cast"), \
1237          (underlying_type) (expr))
1238 #define unvolatize(underlying_type, expr) \
1239         (StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), volatile underlying_type), \
1240                                           "wrong cast"), \
1241          (underlying_type) (expr))
1242 #else
1243 #define unconstify(underlying_type, expr) \
1244         ((underlying_type) (expr))
1245 #define unvolatize(underlying_type, expr) \
1246         ((underlying_type) (expr))
1247 #endif
1248
1249 /* ----------------------------------------------------------------
1250  *                              Section 9: system-specific hacks
1251  *
1252  *              This should be limited to things that absolutely have to be
1253  *              included in every source file.  The port-specific header file
1254  *              is usually a better place for this sort of thing.
1255  * ----------------------------------------------------------------
1256  */
1257
1258 /*
1259  *      NOTE:  this is also used for opening text files.
1260  *      WIN32 treats Control-Z as EOF in files opened in text mode.
1261  *      Therefore, we open files in binary mode on Win32 so we can read
1262  *      literal control-Z.  The other affect is that we see CRLF, but
1263  *      that is OK because we can already handle those cleanly.
1264  */
1265 #if defined(WIN32) || defined(__CYGWIN__)
1266 #define PG_BINARY       O_BINARY
1267 #define PG_BINARY_A "ab"
1268 #define PG_BINARY_R "rb"
1269 #define PG_BINARY_W "wb"
1270 #else
1271 #define PG_BINARY       0
1272 #define PG_BINARY_A "a"
1273 #define PG_BINARY_R "r"
1274 #define PG_BINARY_W "w"
1275 #endif
1276
1277 /*
1278  * Provide prototypes for routines not present in a particular machine's
1279  * standard C library.
1280  */
1281
1282 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
1283 extern int      fdatasync(int fildes);
1284 #endif
1285
1286 /* Older platforms may provide strto[u]ll functionality under other names */
1287 #if !defined(HAVE_STRTOLL) && defined(HAVE___STRTOLL)
1288 #define strtoll __strtoll
1289 #define HAVE_STRTOLL 1
1290 #endif
1291
1292 #if !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
1293 #define strtoll strtoq
1294 #define HAVE_STRTOLL 1
1295 #endif
1296
1297 #if !defined(HAVE_STRTOULL) && defined(HAVE___STRTOULL)
1298 #define strtoull __strtoull
1299 #define HAVE_STRTOULL 1
1300 #endif
1301
1302 #if !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
1303 #define strtoull strtouq
1304 #define HAVE_STRTOULL 1
1305 #endif
1306
1307 #if defined(HAVE_STRTOLL) && !HAVE_DECL_STRTOLL
1308 extern long long strtoll(const char *str, char **endptr, int base);
1309 #endif
1310
1311 #if defined(HAVE_STRTOULL) && !HAVE_DECL_STRTOULL
1312 extern unsigned long long strtoull(const char *str, char **endptr, int base);
1313 #endif
1314
1315 /* no special DLL markers on most ports */
1316 #ifndef PGDLLIMPORT
1317 #define PGDLLIMPORT
1318 #endif
1319 #ifndef PGDLLEXPORT
1320 #define PGDLLEXPORT
1321 #endif
1322
1323 /*
1324  * The following is used as the arg list for signal handlers.  Any ports
1325  * that take something other than an int argument should override this in
1326  * their pg_config_os.h file.  Note that variable names are required
1327  * because it is used in both the prototypes as well as the definitions.
1328  * Note also the long name.  We expect that this won't collide with
1329  * other names causing compiler warnings.
1330  */
1331
1332 #ifndef SIGNAL_ARGS
1333 #define SIGNAL_ARGS  int postgres_signal_arg
1334 #endif
1335
1336 /*
1337  * When there is no sigsetjmp, its functionality is provided by plain
1338  * setjmp.  We now support the case only on Windows.  However, it seems
1339  * that MinGW-64 has some longstanding issues in its setjmp support,
1340  * so on that toolchain we cheat and use gcc's builtins.
1341  */
1342 #ifdef WIN32
1343 #ifdef __MINGW64__
1344 typedef intptr_t sigjmp_buf[5];
1345 #define sigsetjmp(x,y) __builtin_setjmp(x)
1346 #define siglongjmp __builtin_longjmp
1347 #else                                                   /* !__MINGW64__ */
1348 #define sigjmp_buf jmp_buf
1349 #define sigsetjmp(x,y) setjmp(x)
1350 #define siglongjmp longjmp
1351 #endif                                                  /* __MINGW64__ */
1352 #endif                                                  /* WIN32 */
1353
1354 /* EXEC_BACKEND defines */
1355 #ifdef EXEC_BACKEND
1356 #define NON_EXEC_STATIC
1357 #else
1358 #define NON_EXEC_STATIC static
1359 #endif
1360
1361 /* /port compatibility functions */
1362 #include "port.h"
1363
1364 #endif                                                  /* C_H */