1 /*-------------------------------------------------------------------------
4 * Fundamental C definitions. This is included by every .c file in
5 * PostgreSQL (via either postgres.h or postgres_fe.h, as appropriate).
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...
12 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
13 * Portions Copyright (c) 1994, Regents of the University of California
17 *-------------------------------------------------------------------------
20 *----------------------------------------------------------------
23 * When adding stuff to this file, please try to put stuff
24 * into the relevant section, or add new sections as appropriate.
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
36 * 8) system-specific hacks
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.
42 *----------------------------------------------------------------
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.
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
57 #include "pg_config_os.h" /* must be before any system header files */
59 #include "postgres_ext.h"
61 #if _MSC_VER >= 1400 || defined(HAVE_CRTDEFS_H)
62 #define errcode __msvc_errcode
78 #include <sys/types.h>
81 #if defined(WIN32) || defined(__CYGWIN__)
82 #include <fcntl.h> /* ensure O_BINARY is available */
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"
90 /* Must be before gettext() games below */
93 #define _(x) gettext(x)
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))
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
110 * http://www.gnu.org/software/autoconf/manual/gettext/Special-cases.html
112 #define gettext_noop(x) (x)
115 /* ----------------------------------------------------------------
116 * Section 1: hacks to cope with non-ANSI C compilers
118 * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
119 * ----------------------------------------------------------------
124 * Convert the argument to a string, using the C preprocessor.
126 * Concatenate two arguments together, using the C preprocessor.
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.
131 #if defined(HAVE_STRINGIZE)
133 #define CppAsString(identifier) #identifier
134 #define CppConcat(x, y) x##y
135 #else /* !HAVE_STRINGIZE */
137 #define CppAsString(identifier) "identifier"
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
147 #define _priv_CppIdentity(x)x
148 #define CppConcat(x, y) _priv_CppIdentity(x)y
149 #endif /* !HAVE_STRINGIZE */
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
155 #ifdef __GNUC__ /* GNU cc */
156 #define dummyret void
158 #define dummyret char
162 #define __attribute__(_arg_)
165 /* ----------------------------------------------------------------
166 * Section 2: bool, true, false, TRUE, FALSE, NULL
167 * ----------------------------------------------------------------
172 * Boolean value, either true or false.
174 * XXX for C++ compilers, we assume the compiler has a compatible
175 * built-in definition of bool.
185 #define true ((bool) 1)
189 #define false ((bool) 0)
193 typedef bool *BoolPtr;
208 #define NULL ((void *) 0)
212 /* ----------------------------------------------------------------
213 * Section 3: standard system types
214 * ----------------------------------------------------------------
219 * Variable holding address of any memory resident object.
221 * XXX Pointer arithmetic is done with this, so it can't be void *
222 * under "true" ANSI compilers.
224 typedef char *Pointer;
228 * Signed integer, EXACTLY N BITS IN SIZE,
229 * used for numerical computations and the
230 * frontend/backend protocol.
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 */
240 * Unsigned integer, EXACTLY N BITS IN SIZE,
241 * used for numerical computations and the
242 * frontend/backend protocol.
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 */
252 * Unit of bitwise operation, AT LEAST N BITS IN SIZE.
254 typedef uint8 bits8; /* >= 8 bits */
255 typedef uint16 bits16; /* >= 16 bits */
256 typedef uint32 bits32; /* >= 32 bits */
261 #ifdef HAVE_LONG_INT_64
262 /* Plain "long int" fits, use it */
265 typedef long int int64;
268 typedef unsigned long int uint64;
270 #elif defined(HAVE_LONG_LONG_INT_64)
271 /* We have working support for "long long int", use that */
274 typedef long long int int64;
277 typedef unsigned long long int uint64;
280 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
281 #error must have a working 64-bit integer datatype
284 /* Decide if we need to decorate 64-bit constants */
285 #ifdef HAVE_LL_CONSTANTS
286 #define INT64CONST(x) ((int64) x##LL)
287 #define UINT64CONST(x) ((uint64) x##ULL)
289 #define INT64CONST(x) ((int64) x)
290 #define UINT64CONST(x) ((uint64) x)
294 /* Select timestamp representation (float8 or int64) */
295 #ifdef USE_INTEGER_DATETIMES
296 #define HAVE_INT64_TIMESTAMP
299 /* sig_atomic_t is required by ANSI C, but may be missing on old platforms */
300 #ifndef HAVE_SIG_ATOMIC_T
301 typedef int sig_atomic_t;
306 * Size of any memory resident object, as returned by sizeof.
312 * Index into any memory resident array.
315 * Indices are non negative.
317 typedef unsigned int Index;
321 * Offset into any memory resident array.
324 * This differs from an Index in that an Index is always
325 * non negative, whereas Offset may be negative.
327 typedef signed int Offset;
330 * Common Postgres datatype names (as used in the catalogs)
332 typedef float float4;
333 typedef double float8;
336 * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
340 /* typedef Oid is in postgres_ext.h */
343 * regproc is the type name used in the include/catalog headers, but
344 * RegProcedure is the preferred name in C code.
347 typedef regproc RegProcedure;
349 typedef uint32 TransactionId;
351 typedef uint32 LocalTransactionId;
353 typedef uint32 SubTransactionId;
355 #define InvalidSubTransactionId ((SubTransactionId) 0)
356 #define TopSubTransactionId ((SubTransactionId) 1)
358 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
359 typedef TransactionId MultiXactId;
361 typedef uint32 MultiXactOffset;
363 typedef uint32 CommandId;
365 #define FirstCommandId ((CommandId) 0)
368 * Array indexing support
377 * Variable-length datatypes all share the 'struct varlena' header.
379 * NOTE: for TOASTable types, this is an oversimplification, since the value
380 * may be compressed or moved out-of-line. However datatype-specific routines
381 * are mostly content to deal with de-TOASTed values only, and of course
382 * client-side routines should never see a TOASTed value. But even in a
383 * de-TOASTed value, beware of touching vl_len_ directly, as its representation
384 * is no longer convenient. It's recommended that code always use the VARDATA,
385 * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
386 * the struct fields. See postgres.h for details of the TOASTed form.
391 char vl_len_[4]; /* Do not touch this field directly! */
395 #define VARHDRSZ ((int32) sizeof(int32))
398 * These widely-used datatypes are just a varlena header and the data bytes.
399 * There is no terminating null or anything like that --- the data length is
400 * always VARSIZE(ptr) - VARHDRSZ.
402 typedef struct varlena bytea;
403 typedef struct varlena text;
404 typedef struct varlena BpChar; /* blank-padded char, ie SQL char(n) */
405 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
408 * Specialized array types. These are physically laid out just the same
409 * as regular arrays (so that the regular array subscripting code works
410 * with them). They exist as distinct types mostly for historical reasons:
411 * they have nonstandard I/O behavior which we don't want to change for fear
412 * of breaking applications that look at the system catalogs. There is also
413 * an implementation issue for oidvector: it's part of the primary key for
414 * pg_proc, and we can't use the normal btree array support routines for that
415 * without circularity.
419 int32 vl_len_; /* these fields must match ArrayType! */
420 int ndim; /* always 1 for int2vector */
421 int32 dataoffset; /* always 0 for int2vector */
425 int16 values[1]; /* VARIABLE LENGTH ARRAY */
426 } int2vector; /* VARIABLE LENGTH STRUCT */
430 int32 vl_len_; /* these fields must match ArrayType! */
431 int ndim; /* always 1 for oidvector */
432 int32 dataoffset; /* always 0 for oidvector */
436 Oid values[1]; /* VARIABLE LENGTH ARRAY */
437 } oidvector; /* VARIABLE LENGTH STRUCT */
440 * Representation of a Name: effectively just a C string, but null-padded to
441 * exactly NAMEDATALEN bytes. The use of a struct is historical.
443 typedef struct nameData
445 char data[NAMEDATALEN];
447 typedef NameData *Name;
449 #define NameStr(name) ((name).data)
452 * Support macros for escaping strings. escape_backslash should be TRUE
453 * if generating a non-standard-conforming string. Prefixing a string
454 * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
455 * Beware of multiple evaluation of the "ch" argument!
457 #define SQL_STR_DOUBLE(ch, escape_backslash) \
458 ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
460 #define ESCAPE_STRING_SYNTAX 'E'
462 /* ----------------------------------------------------------------
463 * Section 4: IsValid macros for system types
464 * ----------------------------------------------------------------
468 * True iff bool is valid.
470 #define BoolIsValid(boolean) ((boolean) == false || (boolean) == true)
474 * True iff pointer is valid.
476 #define PointerIsValid(pointer) ((const void*)(pointer) != NULL)
480 * True iff pointer is properly aligned to point to the given type.
482 #define PointerIsAligned(pointer, type) \
483 (((intptr_t)(pointer) % (sizeof (type))) == 0)
485 #define OidIsValid(objectId) ((bool) ((objectId) != InvalidOid))
487 #define RegProcedureIsValid(p) OidIsValid(p)
490 /* ----------------------------------------------------------------
491 * Section 5: offsetof, lengthof, endof, alignment
492 * ----------------------------------------------------------------
496 * Offset of a structure/union field within that structure/union.
498 * XXX This is supposed to be part of stddef.h, but isn't on
499 * some systems (like SunOS 4).
502 #define offsetof(type, field) ((long) &((type *)0)->field)
503 #endif /* offsetof */
507 * Number of elements in an array.
509 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
513 * Address of the element one past the last in an array.
515 #define endof(array) (&(array)[lengthof(array)])
518 * Alignment macros: align a length or address appropriately for a given type.
519 * The fooALIGN() macros round up to a multiple of the required alignment,
520 * while the fooALIGN_DOWN() macros round down. The latter are more useful
521 * for problems like "how many X-sized structures will fit in a page?".
523 * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
524 * That case seems extremely unlikely to be needed in practice, however.
528 #define TYPEALIGN(ALIGNVAL,LEN) \
529 (((intptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((intptr_t) ((ALIGNVAL) - 1)))
531 #define SHORTALIGN(LEN) TYPEALIGN(ALIGNOF_SHORT, (LEN))
532 #define INTALIGN(LEN) TYPEALIGN(ALIGNOF_INT, (LEN))
533 #define LONGALIGN(LEN) TYPEALIGN(ALIGNOF_LONG, (LEN))
534 #define DOUBLEALIGN(LEN) TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
535 #define MAXALIGN(LEN) TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
536 /* MAXALIGN covers only built-in types, not buffers */
537 #define BUFFERALIGN(LEN) TYPEALIGN(ALIGNOF_BUFFER, (LEN))
539 #define TYPEALIGN_DOWN(ALIGNVAL,LEN) \
540 (((intptr_t) (LEN)) & ~((intptr_t) ((ALIGNVAL) - 1)))
542 #define SHORTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
543 #define INTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
544 #define LONGALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
545 #define DOUBLEALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
546 #define MAXALIGN_DOWN(LEN) TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
548 /* ----------------------------------------------------------------
549 * Section 6: widely useful macros
550 * ----------------------------------------------------------------
554 * Return the maximum of two numbers.
556 #define Max(x, y) ((x) > (y) ? (x) : (y))
560 * Return the minimum of two numbers.
562 #define Min(x, y) ((x) < (y) ? (x) : (y))
566 * Return the absolute value of the argument.
568 #define Abs(x) ((x) >= 0 ? (x) : -(x))
572 * Like standard library function strncpy(), except that result string
573 * is guaranteed to be null-terminated --- that is, at most N-1 bytes
574 * of the source string will be kept.
575 * Also, the macro returns no result (too hard to do that without
576 * evaluating the arguments multiple times, which seems worse).
578 * BTW: when you need to copy a non-null-terminated string (like a text
579 * datum) and add a null, do not do it with StrNCpy(..., len+1). That
580 * might seem to work, but it fetches one byte more than there is in the
581 * text object. One fine day you'll have a SIGSEGV because there isn't
582 * another byte before the end of memory. Don't laugh, we've had real
583 * live bug reports from real live users over exactly this mistake.
584 * Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
586 #define StrNCpy(dst,src,len) \
589 char * _dst = (dst); \
594 strncpy(_dst, (src), _len); \
595 _dst[_len-1] = '\0'; \
600 /* Get a bit mask of the bits set in non-long aligned addresses */
601 #define LONG_ALIGN_MASK (sizeof(long) - 1)
605 * Exactly the same as standard library function memset(), but considerably
606 * faster for zeroing small word-aligned structures (such as parsetree nodes).
607 * This has to be a macro because the main point is to avoid function-call
608 * overhead. However, we have also found that the loop is faster than
609 * native libc memset() on some platforms, even those with assembler
610 * memset() functions. More research needs to be done, perhaps with
611 * MEMSET_LOOP_LIMIT tests in configure.
613 #define MemSet(start, val, len) \
616 /* must be void* because we don't know if it is integer aligned yet */ \
617 void *_vstart = (void *) (start); \
621 if ((((intptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
622 (_len & LONG_ALIGN_MASK) == 0 && \
624 _len <= MEMSET_LOOP_LIMIT && \
626 * If MEMSET_LOOP_LIMIT == 0, optimizer should find \
627 * the whole "if" false at compile time. \
629 MEMSET_LOOP_LIMIT != 0) \
631 long *_start = (long *) _vstart; \
632 long *_stop = (long *) ((char *) _start + _len); \
633 while (_start < _stop) \
637 memset(_vstart, _val, _len); \
641 * MemSetAligned is the same as MemSet except it omits the test to see if
642 * "start" is word-aligned. This is okay to use if the caller knows a-priori
643 * that the pointer is suitably aligned (typically, because he just got it
644 * from palloc(), which always delivers a max-aligned pointer).
646 #define MemSetAligned(start, val, len) \
649 long *_start = (long *) (start); \
653 if ((_len & LONG_ALIGN_MASK) == 0 && \
655 _len <= MEMSET_LOOP_LIMIT && \
656 MEMSET_LOOP_LIMIT != 0) \
658 long *_stop = (long *) ((char *) _start + _len); \
659 while (_start < _stop) \
663 memset(_start, _val, _len); \
668 * MemSetTest/MemSetLoop are a variant version that allow all the tests in
669 * MemSet to be done at compile time in cases where "val" and "len" are
670 * constants *and* we know the "start" pointer must be word-aligned.
671 * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
672 * MemSetAligned. Beware of multiple evaluations of the arguments when using
675 #define MemSetTest(val, len) \
676 ( ((len) & LONG_ALIGN_MASK) == 0 && \
677 (len) <= MEMSET_LOOP_LIMIT && \
678 MEMSET_LOOP_LIMIT != 0 && \
681 #define MemSetLoop(start, val, len) \
684 long * _start = (long *) (start); \
685 long * _stop = (long *) ((char *) _start + (Size) (len)); \
687 while (_start < _stop) \
692 /* ----------------------------------------------------------------
693 * Section 7: random stuff
694 * ----------------------------------------------------------------
698 #define HIGHBIT (0x80)
699 #define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)
701 #define STATUS_OK (0)
702 #define STATUS_ERROR (-1)
703 #define STATUS_EOF (-2)
704 #define STATUS_FOUND (1)
705 #define STATUS_WAITING (2)
709 * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
710 * used in assert-enabled builds, to avoid compiler warnings about unused
711 * variables in assert-disabled builds.
713 #ifdef USE_ASSERT_CHECKING
714 #define PG_USED_FOR_ASSERTS_ONLY
716 #define PG_USED_FOR_ASSERTS_ONLY __attribute__((unused))
720 /* gettext domain name mangling */
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.
733 * Make sure this matches the installation rules in nls-global.mk.
736 /* need a second indirection because we want to stringize the macro value, not the name */
737 #define CppAsString2(x) CppAsString(x)
739 #ifdef SO_MAJOR_VERSION
740 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
742 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
746 /* ----------------------------------------------------------------
747 * Section 8: system-specific hacks
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 * ----------------------------------------------------------------
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.
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"
769 #define PG_BINARY_A "a"
770 #define PG_BINARY_R "r"
771 #define PG_BINARY_W "w"
775 * Provide prototypes for routines not present in a particular machine's
776 * standard C library.
779 #if !HAVE_DECL_SNPRINTF
781 snprintf(char *str, size_t count, const char *fmt,...)
782 /* This extension allows gcc to check the format string */
783 __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
786 #if !HAVE_DECL_VSNPRINTF
787 extern int vsnprintf(char *str, size_t count, const char *fmt, va_list args);
790 #if !defined(HAVE_MEMMOVE) && !defined(memmove)
791 #define memmove(d, s, c) bcopy(s, d, c)
794 /* no special DLL markers on most ports */
803 * The following is used as the arg list for signal handlers. Any ports
804 * that take something other than an int argument should override this in
805 * their pg_config_os.h file. Note that variable names are required
806 * because it is used in both the prototypes as well as the definitions.
807 * Note also the long name. We expect that this won't collide with
808 * other names causing compiler warnings.
812 #define SIGNAL_ARGS int postgres_signal_arg
816 * When there is no sigsetjmp, its functionality is provided by plain
817 * setjmp. Incidentally, nothing provides setjmp's functionality in
820 #ifndef HAVE_SIGSETJMP
821 #define sigjmp_buf jmp_buf
822 #define sigsetjmp(x,y) setjmp(x)
823 #define siglongjmp longjmp
826 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
827 extern int fdatasync(int fildes);
830 /* If strtoq() exists, rename it to the more standard strtoll() */
831 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
832 #define strtoll strtoq
833 #define HAVE_STRTOLL 1
836 /* If strtouq() exists, rename it to the more standard strtoull() */
837 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
838 #define strtoull strtouq
839 #define HAVE_STRTOULL 1
843 * We assume if we have these two functions, we have their friends too, and
844 * can use the wide-character functions.
846 #if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
847 #define USE_WIDE_UPPER_LOWER
850 /* EXEC_BACKEND defines */
852 #define NON_EXEC_STATIC
854 #define NON_EXEC_STATIC static
857 /* /port compatibility functions */