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) 1996-2008, 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 #endif
 100
 101 /*
 102  *      Use this to mark string constants as needing translation at some later
 103  *      time, rather than immediately.  This is useful for cases where you need
 104  *      access to the original string and translated string, and for cases where
 105  *      immediate translation is not possible, like when initializing global
 106  *      variables.
 107  *              http://www.gnu.org/software/autoconf/manual/gettext/Special-cases.html
 108  */
 109 #define gettext_noop(x) (x)
 110
 111
 112 /* ----------------------------------------------------------------
 113  *                              Section 1: hacks to cope with non-ANSI C compilers
 114  *
 115  * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
 116  * ----------------------------------------------------------------
 117  */
 118
 119 /*
 120  * CppAsString
 121  *              Convert the argument to a string, using the C preprocessor.
 122  * CppConcat
 123  *              Concatenate two arguments together, using the C preprocessor.
 124  *
 125  * Note: the standard Autoconf macro AC_C_STRINGIZE actually only checks
 126  * whether #identifier works, but if we have that we likely have ## too.
 127  */
 128 #if defined(HAVE_STRINGIZE)
 129
 130 #define CppAsString(identifier) #identifier
 131 #define CppConcat(x, y)                 x##y
 132 #else                                                   /* !HAVE_STRINGIZE */
 133
 134 #define CppAsString(identifier) "identifier"
 135
 136 /*
 137  * CppIdentity -- On Reiser based cpp's this is used to concatenate
 138  *              two tokens.  That is
 139  *                              CppIdentity(A)B ==> AB
 140  *              We renamed it to _private_CppIdentity because it should not
 141  *              be referenced outside this file.  On other cpp's it
 142  *              produces  A  B.
 143  */
 144 #define _priv_CppIdentity(x)x
 145 #define CppConcat(x, y)                 _priv_CppIdentity(x)y
 146 #endif   /* !HAVE_STRINGIZE */
 147
 148 /*
 149  * dummyret is used to set return values in macros that use ?: to make
 150  * assignments.  gcc wants these to be void, other compilers like char
 151  */
 152 #ifdef __GNUC__                                 /* GNU cc */
 153 #define dummyret        void
 154 #else
 155 #define dummyret        char
 156 #endif
 157
 158 #ifndef __GNUC__
 159 #define __attribute__(_arg_)
 160 #endif
 161
 162 /* ----------------------------------------------------------------
 163  *                              Section 2:      bool, true, false, TRUE, FALSE, NULL
 164  * ----------------------------------------------------------------
 165  */
 166
 167 /*
 168  * bool
 169  *              Boolean value, either true or false.
 170  *
 171  * XXX for C++ compilers, we assume the compiler has a compatible
 172  * built-in definition of bool.
 173  */
 174
 175 #ifndef __cplusplus
 176
 177 #ifndef bool
 178 typedef char bool;
 179 #endif
 180
 181 #ifndef true
 182 #define true    ((bool) 1)
 183 #endif
 184
 185 #ifndef false
 186 #define false   ((bool) 0)
 187 #endif
 188 #endif   /* not C++ */
 189
 190 typedef bool *BoolPtr;
 191
 192 #ifndef TRUE
 193 #define TRUE    1
 194 #endif
 195
 196 #ifndef FALSE
 197 #define FALSE   0
 198 #endif
 199
 200 /*
 201  * NULL
 202  *              Null pointer.
 203  */
 204 #ifndef NULL
 205 #define NULL    ((void *) 0)
 206 #endif
 207
 208
 209 /* ----------------------------------------------------------------
 210  *                              Section 3:      standard system types
 211  * ----------------------------------------------------------------
 212  */
 213
 214 /*
 215  * Pointer
 216  *              Variable holding address of any memory resident object.
 217  *
 218  *              XXX Pointer arithmetic is done with this, so it can't be void *
 219  *              under "true" ANSI compilers.
 220  */
 221 typedef char *Pointer;
 222
 223 /*
 224  * intN
 225  *              Signed integer, EXACTLY N BITS IN SIZE,
 226  *              used for numerical computations and the
 227  *              frontend/backend protocol.
 228  */
 229 #ifndef HAVE_INT8
 230 typedef signed char int8;               /* == 8 bits */
 231 typedef signed short int16;             /* == 16 bits */
 232 typedef signed int int32;               /* == 32 bits */
 233 #endif   /* not HAVE_INT8 */
 234
 235 /*
 236  * uintN
 237  *              Unsigned integer, EXACTLY N BITS IN SIZE,
 238  *              used for numerical computations and the
 239  *              frontend/backend protocol.
 240  */
 241 #ifndef HAVE_UINT8
 242 typedef unsigned char uint8;    /* == 8 bits */
 243 typedef unsigned short uint16;  /* == 16 bits */
 244 typedef unsigned int uint32;    /* == 32 bits */
 245 #endif   /* not HAVE_UINT8 */
 246
 247 /*
 248  * bitsN
 249  *              Unit of bitwise operation, AT LEAST N BITS IN SIZE.
 250  */
 251 typedef uint8 bits8;                    /* >= 8 bits */
 252 typedef uint16 bits16;                  /* >= 16 bits */
 253 typedef uint32 bits32;                  /* >= 32 bits */
 254
 255 /*
 256  * 64-bit integers
 257  */
 258 #ifdef HAVE_LONG_INT_64
 259 /* Plain "long int" fits, use it */
 260
 261 #ifndef HAVE_INT64
 262 typedef long int int64;
 263 #endif
 264 #ifndef HAVE_UINT64
 265 typedef unsigned long int uint64;
 266 #endif
 267 #elif defined(HAVE_LONG_LONG_INT_64)
 268 /* We have working support for "long long int", use that */
 269
 270 #ifndef HAVE_INT64
 271 typedef long long int int64;
 272 #endif
 273 #ifndef HAVE_UINT64
 274 typedef unsigned long long int uint64;
 275 #endif
 276 #else                                                   /* not HAVE_LONG_INT_64 and not
 277                                                                  * HAVE_LONG_LONG_INT_64 */
 278
 279 /* Won't actually work, but fall back to long int so that code compiles */
 280 #ifndef HAVE_INT64
 281 typedef long int int64;
 282 #endif
 283 #ifndef HAVE_UINT64
 284 typedef unsigned long int uint64;
 285 #endif
 286
 287 #define INT64_IS_BUSTED
 288 #endif   /* not HAVE_LONG_INT_64 and not
 289                                                                  * HAVE_LONG_LONG_INT_64 */
 290
 291 /* Decide if we need to decorate 64-bit constants */
 292 #ifdef HAVE_LL_CONSTANTS
 293 #define INT64CONST(x)  ((int64) x##LL)
 294 #define UINT64CONST(x) ((uint64) x##ULL)
 295 #else
 296 #define INT64CONST(x)  ((int64) x)
 297 #define UINT64CONST(x) ((uint64) x)
 298 #endif
 299
 300
 301 /* Select timestamp representation (float8 or int64) */
 302 #if defined(USE_INTEGER_DATETIMES) && !defined(INT64_IS_BUSTED)
 303 #define HAVE_INT64_TIMESTAMP
 304 #endif
 305
 306 /* sig_atomic_t is required by ANSI C, but may be missing on old platforms */
 307 #ifndef HAVE_SIG_ATOMIC_T
 308 typedef int sig_atomic_t;
 309 #endif
 310
 311 /*
 312  * Size
 313  *              Size of any memory resident object, as returned by sizeof.
 314  */
 315 typedef size_t Size;
 316
 317 /*
 318  * Index
 319  *              Index into any memory resident array.
 320  *
 321  * Note:
 322  *              Indices are non negative.
 323  */
 324 typedef unsigned int Index;
 325
 326 /*
 327  * Offset
 328  *              Offset into any memory resident array.
 329  *
 330  * Note:
 331  *              This differs from an Index in that an Index is always
 332  *              non negative, whereas Offset may be negative.
 333  */
 334 typedef signed int Offset;
 335
 336 /*
 337  * Common Postgres datatype names (as used in the catalogs)
 338  */
 339 typedef int16 int2;
 340 typedef int32 int4;
 341 typedef float float4;
 342 typedef double float8;
 343
 344 /*
 345  * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
 346  * CommandId
 347  */
 348
 349 /* typedef Oid is in postgres_ext.h */
 350
 351 /*
 352  * regproc is the type name used in the include/catalog headers, but
 353  * RegProcedure is the preferred name in C code.
 354  */
 355 typedef Oid regproc;
 356 typedef regproc RegProcedure;
 357
 358 typedef uint32 TransactionId;
 359
 360 typedef uint32 LocalTransactionId;
 361
 362 typedef uint32 SubTransactionId;
 363
 364 #define InvalidSubTransactionId         ((SubTransactionId) 0)
 365 #define TopSubTransactionId                     ((SubTransactionId) 1)
 366
 367 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
 368 typedef TransactionId MultiXactId;
 369
 370 typedef uint32 MultiXactOffset;
 371
 372 typedef uint32 CommandId;
 373
 374 #define FirstCommandId  ((CommandId) 0)
 375
 376 /*
 377  * Array indexing support
 378  */
 379 #define MAXDIM 6
 380 typedef struct
 381 {
 382         int                     indx[MAXDIM];
 383 } IntArray;
 384
 385 /* ----------------
 386  *              Variable-length datatypes all share the 'struct varlena' header.
 387  *
 388  * NOTE: for TOASTable types, this is an oversimplification, since the value
 389  * may be compressed or moved out-of-line.      However datatype-specific routines
 390  * are mostly content to deal with de-TOASTed values only, and of course
 391  * client-side routines should never see a TOASTed value.  But even in a
 392  * de-TOASTed value, beware of touching vl_len_ directly, as its representation
 393  * is no longer convenient.  It's recommended that code always use the VARDATA,
 394  * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
 395  * the struct fields.  See postgres.h for details of the TOASTed form.
 396  * ----------------
 397  */
 398 struct varlena
 399 {
 400         char            vl_len_[4];             /* Do not touch this field directly! */
 401         char            vl_dat[1];
 402 };
 403
 404 #define VARHDRSZ                ((int32) sizeof(int32))
 405
 406 /*
 407  * These widely-used datatypes are just a varlena header and the data bytes.
 408  * There is no terminating null or anything like that --- the data length is
 409  * always VARSIZE(ptr) - VARHDRSZ.
 410  */
 411 typedef struct varlena bytea;
 412 typedef struct varlena text;
 413 typedef struct varlena BpChar;  /* blank-padded char, ie SQL char(n) */
 414 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
 415
 416 /*
 417  * Specialized array types.  These are physically laid out just the same
 418  * as regular arrays (so that the regular array subscripting code works
 419  * with them).  They exist as distinct types mostly for historical reasons:
 420  * they have nonstandard I/O behavior which we don't want to change for fear
 421  * of breaking applications that look at the system catalogs.  There is also
 422  * an implementation issue for oidvector: it's part of the primary key for
 423  * pg_proc, and we can't use the normal btree array support routines for that
 424  * without circularity.
 425  */
 426 typedef struct
 427 {
 428         int32           vl_len_;                /* these fields must match ArrayType! */
 429         int                     ndim;                   /* always 1 for int2vector */
 430         int32           dataoffset;             /* always 0 for int2vector */
 431         Oid                     elemtype;
 432         int                     dim1;
 433         int                     lbound1;
 434         int2            values[1];              /* VARIABLE LENGTH ARRAY */
 435 } int2vector;                                   /* VARIABLE LENGTH STRUCT */
 436
 437 typedef struct
 438 {
 439         int32           vl_len_;                /* these fields must match ArrayType! */
 440         int                     ndim;                   /* always 1 for oidvector */
 441         int32           dataoffset;             /* always 0 for oidvector */
 442         Oid                     elemtype;
 443         int                     dim1;
 444         int                     lbound1;
 445         Oid                     values[1];              /* VARIABLE LENGTH ARRAY */
 446 } oidvector;                                    /* VARIABLE LENGTH STRUCT */
 447
 448 /*
 449  * Representation of a Name: effectively just a C string, but null-padded to
 450  * exactly NAMEDATALEN bytes.  The use of a struct is historical.
 451  */
 452 typedef struct nameData
 453 {
 454         char            data[NAMEDATALEN];
 455 } NameData;
 456 typedef NameData *Name;
 457
 458 #define NameStr(name)   ((name).data)
 459
 460 /*
 461  * Support macros for escaping strings.  escape_backslash should be TRUE
 462  * if generating a non-standard-conforming string.      Prefixing a string
 463  * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
 464  * Beware of multiple evaluation of the "ch" argument!
 465  */
 466 #define SQL_STR_DOUBLE(ch, escape_backslash)    \
 467         ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
 468
 469 #define ESCAPE_STRING_SYNTAX    'E'
 470
 471 /* ----------------------------------------------------------------
 472  *                              Section 4:      IsValid macros for system types
 473  * ----------------------------------------------------------------
 474  */
 475 /*
 476  * BoolIsValid
 477  *              True iff bool is valid.
 478  */
 479 #define BoolIsValid(boolean)    ((boolean) == false || (boolean) == true)
 480
 481 /*
 482  * PointerIsValid
 483  *              True iff pointer is valid.
 484  */
 485 #define PointerIsValid(pointer) ((void*)(pointer) != NULL)
 486
 487 /*
 488  * PointerIsAligned
 489  *              True iff pointer is properly aligned to point to the given type.
 490  */
 491 #define PointerIsAligned(pointer, type) \
 492                 (((long)(pointer) % (sizeof (type))) == 0)
 493
 494 #define OidIsValid(objectId)  ((bool) ((objectId) != InvalidOid))
 495
 496 #define RegProcedureIsValid(p)  OidIsValid(p)
 497
 498
 499 /* ----------------------------------------------------------------
 500  *                              Section 5:      offsetof, lengthof, endof, alignment
 501  * ----------------------------------------------------------------
 502  */
 503 /*
 504  * offsetof
 505  *              Offset of a structure/union field within that structure/union.
 506  *
 507  *              XXX This is supposed to be part of stddef.h, but isn't on
 508  *              some systems (like SunOS 4).
 509  */
 510 #ifndef offsetof
 511 #define offsetof(type, field)   ((long) &((type *)0)->field)
 512 #endif   /* offsetof */
 513
 514 /*
 515  * lengthof
 516  *              Number of elements in an array.
 517  */
 518 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
 519
 520 /*
 521  * endof
 522  *              Address of the element one past the last in an array.
 523  */
 524 #define endof(array)    (&(array)[lengthof(array)])
 525
 526 /* ----------------
 527  * Alignment macros: align a length or address appropriately for a given type.
 528  * The fooALIGN() macros round up to a multiple of the required alignment,
 529  * while the fooALIGN_DOWN() macros round down.  The latter are more useful
 530  * for problems like "how many X-sized structures will fit in a page?".
 531  *
 532  * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
 533  * That case seems extremely unlikely to be needed in practice, however.
 534  * ----------------
 535  */
 536
 537 #define TYPEALIGN(ALIGNVAL,LEN)  \
 538         (((long) (LEN) + ((ALIGNVAL) - 1)) & ~((long) ((ALIGNVAL) - 1)))
 539
 540 #define SHORTALIGN(LEN)                 TYPEALIGN(ALIGNOF_SHORT, (LEN))
 541 #define INTALIGN(LEN)                   TYPEALIGN(ALIGNOF_INT, (LEN))
 542 #define LONGALIGN(LEN)                  TYPEALIGN(ALIGNOF_LONG, (LEN))
 543 #define DOUBLEALIGN(LEN)                TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
 544 #define MAXALIGN(LEN)                   TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
 545 /* MAXALIGN covers only built-in types, not buffers */
 546 #define BUFFERALIGN(LEN)                TYPEALIGN(ALIGNOF_BUFFER, (LEN))
 547
 548 #define TYPEALIGN_DOWN(ALIGNVAL,LEN)  \
 549         (((long) (LEN)) & ~((long) ((ALIGNVAL) - 1)))
 550
 551 #define SHORTALIGN_DOWN(LEN)    TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
 552 #define INTALIGN_DOWN(LEN)              TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
 553 #define LONGALIGN_DOWN(LEN)             TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
 554 #define DOUBLEALIGN_DOWN(LEN)   TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
 555 #define MAXALIGN_DOWN(LEN)              TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
 556
 557 /* ----------------------------------------------------------------
 558  *                              Section 6:      widely useful macros
 559  * ----------------------------------------------------------------
 560  */
 561 /*
 562  * Max
 563  *              Return the maximum of two numbers.
 564  */
 565 #define Max(x, y)               ((x) > (y) ? (x) : (y))
 566
 567 /*
 568  * Min
 569  *              Return the minimum of two numbers.
 570  */
 571 #define Min(x, y)               ((x) < (y) ? (x) : (y))
 572
 573 /*
 574  * Abs
 575  *              Return the absolute value of the argument.
 576  */
 577 #define Abs(x)                  ((x) >= 0 ? (x) : -(x))
 578
 579 /*
 580  * StrNCpy
 581  *      Like standard library function strncpy(), except that result string
 582  *      is guaranteed to be null-terminated --- that is, at most N-1 bytes
 583  *      of the source string will be kept.
 584  *      Also, the macro returns no result (too hard to do that without
 585  *      evaluating the arguments multiple times, which seems worse).
 586  *
 587  *      BTW: when you need to copy a non-null-terminated string (like a text
 588  *      datum) and add a null, do not do it with StrNCpy(..., len+1).  That
 589  *      might seem to work, but it fetches one byte more than there is in the
 590  *      text object.  One fine day you'll have a SIGSEGV because there isn't
 591  *      another byte before the end of memory.  Don't laugh, we've had real
 592  *      live bug reports from real live users over exactly this mistake.
 593  *      Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
 594  */
 595 #define StrNCpy(dst,src,len) \
 596         do \
 597         { \
 598                 char * _dst = (dst); \
 599                 Size _len = (len); \
 600 \
 601                 if (_len > 0) \
 602                 { \
 603                         strncpy(_dst, (src), _len); \
 604                         _dst[_len-1] = '\0'; \
 605                 } \
 606         } while (0)
 607
 608
 609 /* Get a bit mask of the bits set in non-long aligned addresses */
 610 #define LONG_ALIGN_MASK (sizeof(long) - 1)
 611
 612 /*
 613  * MemSet
 614  *      Exactly the same as standard library function memset(), but considerably
 615  *      faster for zeroing small word-aligned structures (such as parsetree nodes).
 616  *      This has to be a macro because the main point is to avoid function-call
 617  *      overhead.       However, we have also found that the loop is faster than
 618  *      native libc memset() on some platforms, even those with assembler
 619  *      memset() functions.  More research needs to be done, perhaps with
 620  *      MEMSET_LOOP_LIMIT tests in configure.
 621  */
 622 #define MemSet(start, val, len) \
 623         do \
 624         { \
 625                 /* must be void* because we don't know if it is integer aligned yet */ \
 626                 void   *_vstart = (void *) (start); \
 627                 int             _val = (val); \
 628                 Size    _len = (len); \
 629 \
 630                 if ((((long) _vstart) & LONG_ALIGN_MASK) == 0 && \
 631                         (_len & LONG_ALIGN_MASK) == 0 && \
 632                         _val == 0 && \
 633                         _len <= MEMSET_LOOP_LIMIT && \
 634                         /* \
 635                          *      If MEMSET_LOOP_LIMIT == 0, optimizer should find \
 636                          *      the whole "if" false at compile time. \
 637                          */ \
 638                         MEMSET_LOOP_LIMIT != 0) \
 639                 { \
 640                         long *_start = (long *) _vstart; \
 641                         long *_stop = (long *) ((char *) _start + _len); \
 642                         while (_start < _stop) \
 643                                 *_start++ = 0; \
 644                 } \
 645                 else \
 646                         memset(_vstart, _val, _len); \
 647         } while (0)
 648
 649 /*
 650  * MemSetAligned is the same as MemSet except it omits the test to see if
 651  * "start" is word-aligned.  This is okay to use if the caller knows a-priori
 652  * that the pointer is suitably aligned (typically, because he just got it
 653  * from palloc(), which always delivers a max-aligned pointer).
 654  */
 655 #define MemSetAligned(start, val, len) \
 656         do \
 657         { \
 658                 long   *_start = (long *) (start); \
 659                 int             _val = (val); \
 660                 Size    _len = (len); \
 661 \
 662                 if ((_len & LONG_ALIGN_MASK) == 0 && \
 663                         _val == 0 && \
 664                         _len <= MEMSET_LOOP_LIMIT && \
 665                         MEMSET_LOOP_LIMIT != 0) \
 666                 { \
 667                         long *_stop = (long *) ((char *) _start + _len); \
 668                         while (_start < _stop) \
 669                                 *_start++ = 0; \
 670                 } \
 671                 else \
 672                         memset(_start, _val, _len); \
 673         } while (0)
 674
 675
 676 /*
 677  * MemSetTest/MemSetLoop are a variant version that allow all the tests in
 678  * MemSet to be done at compile time in cases where "val" and "len" are
 679  * constants *and* we know the "start" pointer must be word-aligned.
 680  * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
 681  * MemSetAligned.  Beware of multiple evaluations of the arguments when using
 682  * this approach.
 683  */
 684 #define MemSetTest(val, len) \
 685         ( ((len) & LONG_ALIGN_MASK) == 0 && \
 686         (len) <= MEMSET_LOOP_LIMIT && \
 687         MEMSET_LOOP_LIMIT != 0 && \
 688         (val) == 0 )
 689
 690 #define MemSetLoop(start, val, len) \
 691         do \
 692         { \
 693                 long * _start = (long *) (start); \
 694                 long * _stop = (long *) ((char *) _start + (Size) (len)); \
 695         \
 696                 while (_start < _stop) \
 697                         *_start++ = 0; \
 698         } while (0)
 699
 700
 701 /* ----------------------------------------------------------------
 702  *                              Section 7:      random stuff
 703  * ----------------------------------------------------------------
 704  */
 705
 706 /* msb for char */
 707 #define HIGHBIT                                 (0x80)
 708 #define IS_HIGHBIT_SET(ch)              ((unsigned char)(ch) & HIGHBIT)
 709
 710 #define STATUS_OK                               (0)
 711 #define STATUS_ERROR                    (-1)
 712 #define STATUS_EOF                              (-2)
 713 #define STATUS_FOUND                    (1)
 714 #define STATUS_WAITING                  (2)
 715
 716
 717 /* ----------------------------------------------------------------
 718  *                              Section 8: system-specific hacks
 719  *
 720  *              This should be limited to things that absolutely have to be
 721  *              included in every source file.  The port-specific header file
 722  *              is usually a better place for this sort of thing.
 723  * ----------------------------------------------------------------
 724  */
 725
 726 /*
 727  *      NOTE:  this is also used for opening text files.
 728  *      WIN32 treats Control-Z as EOF in files opened in text mode.
 729  *      Therefore, we open files in binary mode on Win32 so we can read
 730  *      literal control-Z.      The other affect is that we see CRLF, but
 731  *      that is OK because we can already handle those cleanly.
 732  */
 733 #if defined(WIN32) || defined(__CYGWIN__)
 734 #define PG_BINARY       O_BINARY
 735 #define PG_BINARY_A "ab"
 736 #define PG_BINARY_R "rb"
 737 #define PG_BINARY_W "wb"
 738 #else
 739 #define PG_BINARY       0
 740 #define PG_BINARY_A "a"
 741 #define PG_BINARY_R "r"
 742 #define PG_BINARY_W "w"
 743 #endif
 744
 745 #if defined(sun) && defined(__sparc__) && !defined(__SVR4)
 746 #include <unistd.h>
 747 #endif
 748
 749 /* These are for things that are one way on Unix and another on NT */
 750 #define NULL_DEV                "/dev/null"
 751
 752 /*
 753  * Provide prototypes for routines not present in a particular machine's
 754  * standard C library.
 755  */
 756
 757 #if !HAVE_DECL_SNPRINTF
 758 extern int
 759 snprintf(char *str, size_t count, const char *fmt,...)
 760 /* This extension allows gcc to check the format string */
 761 __attribute__((format(printf, 3, 4)));
 762 #endif
 763
 764 #if !HAVE_DECL_VSNPRINTF
 765 extern int      vsnprintf(char *str, size_t count, const char *fmt, va_list args);
 766 #endif
 767
 768 #if !defined(HAVE_MEMMOVE) && !defined(memmove)
 769 #define memmove(d, s, c)                bcopy(s, d, c)
 770 #endif
 771
 772 #ifndef PGDLLIMPORT
 773 #define PGDLLIMPORT                             /* no special DLL markers on most ports */
 774 #endif
 775
 776 /*
 777  * The following is used as the arg list for signal handlers.  Any ports
 778  * that take something other than an int argument should override this in
 779  * their pg_config_os.h file.  Note that variable names are required
 780  * because it is used in both the prototypes as well as the definitions.
 781  * Note also the long name.  We expect that this won't collide with
 782  * other names causing compiler warnings.
 783  */
 784
 785 #ifndef SIGNAL_ARGS
 786 #define SIGNAL_ARGS  int postgres_signal_arg
 787 #endif
 788
 789 /*
 790  * When there is no sigsetjmp, its functionality is provided by plain
 791  * setjmp. Incidentally, nothing provides setjmp's functionality in
 792  * that case.
 793  */
 794 #ifndef HAVE_SIGSETJMP
 795 #define sigjmp_buf jmp_buf
 796 #define sigsetjmp(x,y) setjmp(x)
 797 #define siglongjmp longjmp
 798 #endif
 799
 800 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
 801 extern int      fdatasync(int fildes);
 802 #endif
 803
 804 /* If strtoq() exists, rename it to the more standard strtoll() */
 805 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
 806 #define strtoll strtoq
 807 #define HAVE_STRTOLL 1
 808 #endif
 809
 810 /* If strtouq() exists, rename it to the more standard strtoull() */
 811 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
 812 #define strtoull strtouq
 813 #define HAVE_STRTOULL 1
 814 #endif
 815
 816 /*
 817  * We assume if we have these two functions, we have their friends too, and
 818  * can use the wide-character functions.
 819  */
 820 #if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
 821 #define USE_WIDE_UPPER_LOWER
 822 #endif
 823
 824 /* EXEC_BACKEND defines */
 825 #ifdef EXEC_BACKEND
 826 #define NON_EXEC_STATIC
 827 #else
 828 #define NON_EXEC_STATIC static
 829 #endif
 830
 831 /* /port compatibility functions */
 832 #include "port.h"
 833
 834 #endif   /* C_H */