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)
334 typedef float float4;
335 typedef double float8;
338 * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
342 /* typedef Oid is in postgres_ext.h */
345 * regproc is the type name used in the include/catalog headers, but
346 * RegProcedure is the preferred name in C code.
349 typedef regproc RegProcedure;
351 typedef uint32 TransactionId;
353 typedef uint32 LocalTransactionId;
355 typedef uint32 SubTransactionId;
357 #define InvalidSubTransactionId ((SubTransactionId) 0)
358 #define TopSubTransactionId ((SubTransactionId) 1)
360 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
361 typedef TransactionId MultiXactId;
363 typedef uint32 MultiXactOffset;
365 typedef uint32 CommandId;
367 #define FirstCommandId ((CommandId) 0)
370 * Array indexing support
379 * Variable-length datatypes all share the 'struct varlena' header.
381 * NOTE: for TOASTable types, this is an oversimplification, since the value
382 * may be compressed or moved out-of-line. However datatype-specific routines
383 * are mostly content to deal with de-TOASTed values only, and of course
384 * client-side routines should never see a TOASTed value. But even in a
385 * de-TOASTed value, beware of touching vl_len_ directly, as its representation
386 * is no longer convenient. It's recommended that code always use the VARDATA,
387 * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
388 * the struct fields. See postgres.h for details of the TOASTed form.
393 char vl_len_[4]; /* Do not touch this field directly! */
397 #define VARHDRSZ ((int32) sizeof(int32))
400 * These widely-used datatypes are just a varlena header and the data bytes.
401 * There is no terminating null or anything like that --- the data length is
402 * always VARSIZE(ptr) - VARHDRSZ.
404 typedef struct varlena bytea;
405 typedef struct varlena text;
406 typedef struct varlena BpChar; /* blank-padded char, ie SQL char(n) */
407 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
410 * Specialized array types. These are physically laid out just the same
411 * as regular arrays (so that the regular array subscripting code works
412 * with them). They exist as distinct types mostly for historical reasons:
413 * they have nonstandard I/O behavior which we don't want to change for fear
414 * of breaking applications that look at the system catalogs. There is also
415 * an implementation issue for oidvector: it's part of the primary key for
416 * pg_proc, and we can't use the normal btree array support routines for that
417 * without circularity.
421 int32 vl_len_; /* these fields must match ArrayType! */
422 int ndim; /* always 1 for int2vector */
423 int32 dataoffset; /* always 0 for int2vector */
427 int2 values[1]; /* VARIABLE LENGTH ARRAY */
428 } int2vector; /* VARIABLE LENGTH STRUCT */
432 int32 vl_len_; /* these fields must match ArrayType! */
433 int ndim; /* always 1 for oidvector */
434 int32 dataoffset; /* always 0 for oidvector */
438 Oid values[1]; /* VARIABLE LENGTH ARRAY */
439 } oidvector; /* VARIABLE LENGTH STRUCT */
442 * Representation of a Name: effectively just a C string, but null-padded to
443 * exactly NAMEDATALEN bytes. The use of a struct is historical.
445 typedef struct nameData
447 char data[NAMEDATALEN];
449 typedef NameData *Name;
451 #define NameStr(name) ((name).data)
454 * Support macros for escaping strings. escape_backslash should be TRUE
455 * if generating a non-standard-conforming string. Prefixing a string
456 * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
457 * Beware of multiple evaluation of the "ch" argument!
459 #define SQL_STR_DOUBLE(ch, escape_backslash) \
460 ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
462 #define ESCAPE_STRING_SYNTAX 'E'
464 /* ----------------------------------------------------------------
465 * Section 4: IsValid macros for system types
466 * ----------------------------------------------------------------
470 * True iff bool is valid.
472 #define BoolIsValid(boolean) ((boolean) == false || (boolean) == true)
476 * True iff pointer is valid.
478 #define PointerIsValid(pointer) ((const void*)(pointer) != NULL)
482 * True iff pointer is properly aligned to point to the given type.
484 #define PointerIsAligned(pointer, type) \
485 (((intptr_t)(pointer) % (sizeof (type))) == 0)
487 #define OidIsValid(objectId) ((bool) ((objectId) != InvalidOid))
489 #define RegProcedureIsValid(p) OidIsValid(p)
492 /* ----------------------------------------------------------------
493 * Section 5: offsetof, lengthof, endof, alignment
494 * ----------------------------------------------------------------
498 * Offset of a structure/union field within that structure/union.
500 * XXX This is supposed to be part of stddef.h, but isn't on
501 * some systems (like SunOS 4).
504 #define offsetof(type, field) ((long) &((type *)0)->field)
505 #endif /* offsetof */
509 * Number of elements in an array.
511 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
515 * Address of the element one past the last in an array.
517 #define endof(array) (&(array)[lengthof(array)])
520 * Alignment macros: align a length or address appropriately for a given type.
521 * The fooALIGN() macros round up to a multiple of the required alignment,
522 * while the fooALIGN_DOWN() macros round down. The latter are more useful
523 * for problems like "how many X-sized structures will fit in a page?".
525 * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
526 * That case seems extremely unlikely to be needed in practice, however.
530 #define TYPEALIGN(ALIGNVAL,LEN) \
531 (((intptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((intptr_t) ((ALIGNVAL) - 1)))
533 #define SHORTALIGN(LEN) TYPEALIGN(ALIGNOF_SHORT, (LEN))
534 #define INTALIGN(LEN) TYPEALIGN(ALIGNOF_INT, (LEN))
535 #define LONGALIGN(LEN) TYPEALIGN(ALIGNOF_LONG, (LEN))
536 #define DOUBLEALIGN(LEN) TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
537 #define MAXALIGN(LEN) TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
538 /* MAXALIGN covers only built-in types, not buffers */
539 #define BUFFERALIGN(LEN) TYPEALIGN(ALIGNOF_BUFFER, (LEN))
541 #define TYPEALIGN_DOWN(ALIGNVAL,LEN) \
542 (((intptr_t) (LEN)) & ~((intptr_t) ((ALIGNVAL) - 1)))
544 #define SHORTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
545 #define INTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
546 #define LONGALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
547 #define DOUBLEALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
548 #define MAXALIGN_DOWN(LEN) TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
550 /* ----------------------------------------------------------------
551 * Section 6: widely useful macros
552 * ----------------------------------------------------------------
556 * Return the maximum of two numbers.
558 #define Max(x, y) ((x) > (y) ? (x) : (y))
562 * Return the minimum of two numbers.
564 #define Min(x, y) ((x) < (y) ? (x) : (y))
568 * Return the absolute value of the argument.
570 #define Abs(x) ((x) >= 0 ? (x) : -(x))
574 * Like standard library function strncpy(), except that result string
575 * is guaranteed to be null-terminated --- that is, at most N-1 bytes
576 * of the source string will be kept.
577 * Also, the macro returns no result (too hard to do that without
578 * evaluating the arguments multiple times, which seems worse).
580 * BTW: when you need to copy a non-null-terminated string (like a text
581 * datum) and add a null, do not do it with StrNCpy(..., len+1). That
582 * might seem to work, but it fetches one byte more than there is in the
583 * text object. One fine day you'll have a SIGSEGV because there isn't
584 * another byte before the end of memory. Don't laugh, we've had real
585 * live bug reports from real live users over exactly this mistake.
586 * Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
588 #define StrNCpy(dst,src,len) \
591 char * _dst = (dst); \
596 strncpy(_dst, (src), _len); \
597 _dst[_len-1] = '\0'; \
602 /* Get a bit mask of the bits set in non-long aligned addresses */
603 #define LONG_ALIGN_MASK (sizeof(long) - 1)
607 * Exactly the same as standard library function memset(), but considerably
608 * faster for zeroing small word-aligned structures (such as parsetree nodes).
609 * This has to be a macro because the main point is to avoid function-call
610 * overhead. However, we have also found that the loop is faster than
611 * native libc memset() on some platforms, even those with assembler
612 * memset() functions. More research needs to be done, perhaps with
613 * MEMSET_LOOP_LIMIT tests in configure.
615 #define MemSet(start, val, len) \
618 /* must be void* because we don't know if it is integer aligned yet */ \
619 void *_vstart = (void *) (start); \
623 if ((((intptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
624 (_len & LONG_ALIGN_MASK) == 0 && \
626 _len <= MEMSET_LOOP_LIMIT && \
628 * If MEMSET_LOOP_LIMIT == 0, optimizer should find \
629 * the whole "if" false at compile time. \
631 MEMSET_LOOP_LIMIT != 0) \
633 long *_start = (long *) _vstart; \
634 long *_stop = (long *) ((char *) _start + _len); \
635 while (_start < _stop) \
639 memset(_vstart, _val, _len); \
643 * MemSetAligned is the same as MemSet except it omits the test to see if
644 * "start" is word-aligned. This is okay to use if the caller knows a-priori
645 * that the pointer is suitably aligned (typically, because he just got it
646 * from palloc(), which always delivers a max-aligned pointer).
648 #define MemSetAligned(start, val, len) \
651 long *_start = (long *) (start); \
655 if ((_len & LONG_ALIGN_MASK) == 0 && \
657 _len <= MEMSET_LOOP_LIMIT && \
658 MEMSET_LOOP_LIMIT != 0) \
660 long *_stop = (long *) ((char *) _start + _len); \
661 while (_start < _stop) \
665 memset(_start, _val, _len); \
670 * MemSetTest/MemSetLoop are a variant version that allow all the tests in
671 * MemSet to be done at compile time in cases where "val" and "len" are
672 * constants *and* we know the "start" pointer must be word-aligned.
673 * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
674 * MemSetAligned. Beware of multiple evaluations of the arguments when using
677 #define MemSetTest(val, len) \
678 ( ((len) & LONG_ALIGN_MASK) == 0 && \
679 (len) <= MEMSET_LOOP_LIMIT && \
680 MEMSET_LOOP_LIMIT != 0 && \
683 #define MemSetLoop(start, val, len) \
686 long * _start = (long *) (start); \
687 long * _stop = (long *) ((char *) _start + (Size) (len)); \
689 while (_start < _stop) \
694 /* ----------------------------------------------------------------
695 * Section 7: random stuff
696 * ----------------------------------------------------------------
700 #define HIGHBIT (0x80)
701 #define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)
703 #define STATUS_OK (0)
704 #define STATUS_ERROR (-1)
705 #define STATUS_EOF (-2)
706 #define STATUS_FOUND (1)
707 #define STATUS_WAITING (2)
711 * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
712 * used in assert-enabled builds, to avoid compiler warnings about unused
713 * variables in assert-disabled builds.
715 #ifdef USE_ASSERT_CHECKING
716 #define PG_USED_FOR_ASSERTS_ONLY
718 #define PG_USED_FOR_ASSERTS_ONLY __attribute__((unused))
722 /* gettext domain name mangling */
725 * To better support parallel installations of major PostgeSQL
726 * versions as well as parallel installations of major library soname
727 * versions, we mangle the gettext domain name by appending those
728 * version numbers. The coding rule ought to be that whereever the
729 * domain name is mentioned as a literal, it must be wrapped into
730 * PG_TEXTDOMAIN(). The macros below do not work on non-literals; but
731 * that is somewhat intentional because it avoids having to worry
732 * about multiple states of premangling and postmangling as the values
733 * are being passed around.
735 * Make sure this matches the installation rules in nls-global.mk.
738 /* need a second indirection because we want to stringize the macro value, not the name */
739 #define CppAsString2(x) CppAsString(x)
741 #ifdef SO_MAJOR_VERSION
742 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
744 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
748 /* ----------------------------------------------------------------
749 * Section 8: system-specific hacks
751 * This should be limited to things that absolutely have to be
752 * included in every source file. The port-specific header file
753 * is usually a better place for this sort of thing.
754 * ----------------------------------------------------------------
758 * NOTE: this is also used for opening text files.
759 * WIN32 treats Control-Z as EOF in files opened in text mode.
760 * Therefore, we open files in binary mode on Win32 so we can read
761 * literal control-Z. The other affect is that we see CRLF, but
762 * that is OK because we can already handle those cleanly.
764 #if defined(WIN32) || defined(__CYGWIN__)
765 #define PG_BINARY O_BINARY
766 #define PG_BINARY_A "ab"
767 #define PG_BINARY_R "rb"
768 #define PG_BINARY_W "wb"
771 #define PG_BINARY_A "a"
772 #define PG_BINARY_R "r"
773 #define PG_BINARY_W "w"
777 * Provide prototypes for routines not present in a particular machine's
778 * standard C library.
781 #if !HAVE_DECL_SNPRINTF
783 snprintf(char *str, size_t count, const char *fmt,...)
784 /* This extension allows gcc to check the format string */
785 __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
788 #if !HAVE_DECL_VSNPRINTF
789 extern int vsnprintf(char *str, size_t count, const char *fmt, va_list args);
792 #if !defined(HAVE_MEMMOVE) && !defined(memmove)
793 #define memmove(d, s, c) bcopy(s, d, c)
796 /* no special DLL markers on most ports */
805 * The following is used as the arg list for signal handlers. Any ports
806 * that take something other than an int argument should override this in
807 * their pg_config_os.h file. Note that variable names are required
808 * because it is used in both the prototypes as well as the definitions.
809 * Note also the long name. We expect that this won't collide with
810 * other names causing compiler warnings.
814 #define SIGNAL_ARGS int postgres_signal_arg
818 * When there is no sigsetjmp, its functionality is provided by plain
819 * setjmp. Incidentally, nothing provides setjmp's functionality in
822 #ifndef HAVE_SIGSETJMP
823 #define sigjmp_buf jmp_buf
824 #define sigsetjmp(x,y) setjmp(x)
825 #define siglongjmp longjmp
828 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
829 extern int fdatasync(int fildes);
832 /* If strtoq() exists, rename it to the more standard strtoll() */
833 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
834 #define strtoll strtoq
835 #define HAVE_STRTOLL 1
838 /* If strtouq() exists, rename it to the more standard strtoull() */
839 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
840 #define strtoull strtouq
841 #define HAVE_STRTOULL 1
845 * We assume if we have these two functions, we have their friends too, and
846 * can use the wide-character functions.
848 #if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
849 #define USE_WIDE_UPPER_LOWER
852 /* EXEC_BACKEND defines */
854 #define NON_EXEC_STATIC
856 #define NON_EXEC_STATIC static
859 /* /port compatibility functions */