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) 1996-2010, PostgreSQL Global Development Group
13 * Portions Copyright (c) 1994, Regents of the University of California
15 * $PostgreSQL: pgsql/src/include/c.h,v 1.239 2010/01/07 04:53:35 tgl Exp $
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"
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 */
84 #ifdef HAVE_SUPPORTDEFS_H
85 #include <SupportDefs.h>
88 #if defined(WIN32) || defined(__CYGWIN__)
89 /* We have to redefine some system functions after they are included above. */
90 #include "pg_config_os.h"
93 /* Must be before gettext() games below */
96 #define _(x) gettext(x)
101 #define gettext(x) (x)
102 #define dgettext(d,x) (x)
103 #define ngettext(s,p,n) ((n) == 1 ? (s) : (p))
104 #define dngettext(d,s,p,n) ((n) == 1 ? (s) : (p))
108 * Use this to mark string constants as needing translation at some later
109 * time, rather than immediately. This is useful for cases where you need
110 * access to the original string and translated string, and for cases where
111 * immediate translation is not possible, like when initializing global
113 * http://www.gnu.org/software/autoconf/manual/gettext/Special-cases.html
115 #define gettext_noop(x) (x)
118 /* ----------------------------------------------------------------
119 * Section 1: hacks to cope with non-ANSI C compilers
121 * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
122 * ----------------------------------------------------------------
127 * Convert the argument to a string, using the C preprocessor.
129 * Concatenate two arguments together, using the C preprocessor.
131 * Note: the standard Autoconf macro AC_C_STRINGIZE actually only checks
132 * whether #identifier works, but if we have that we likely have ## too.
134 #if defined(HAVE_STRINGIZE)
136 #define CppAsString(identifier) #identifier
137 #define CppConcat(x, y) x##y
138 #else /* !HAVE_STRINGIZE */
140 #define CppAsString(identifier) "identifier"
143 * CppIdentity -- On Reiser based cpp's this is used to concatenate
144 * two tokens. That is
145 * CppIdentity(A)B ==> AB
146 * We renamed it to _private_CppIdentity because it should not
147 * be referenced outside this file. On other cpp's it
150 #define _priv_CppIdentity(x)x
151 #define CppConcat(x, y) _priv_CppIdentity(x)y
152 #endif /* !HAVE_STRINGIZE */
155 * dummyret is used to set return values in macros that use ?: to make
156 * assignments. gcc wants these to be void, other compilers like char
158 #ifdef __GNUC__ /* GNU cc */
159 #define dummyret void
161 #define dummyret char
165 #define __attribute__(_arg_)
168 /* ----------------------------------------------------------------
169 * Section 2: bool, true, false, TRUE, FALSE, NULL
170 * ----------------------------------------------------------------
175 * Boolean value, either true or false.
177 * XXX for C++ compilers, we assume the compiler has a compatible
178 * built-in definition of bool.
188 #define true ((bool) 1)
192 #define false ((bool) 0)
196 typedef bool *BoolPtr;
211 #define NULL ((void *) 0)
215 /* ----------------------------------------------------------------
216 * Section 3: standard system types
217 * ----------------------------------------------------------------
222 * Variable holding address of any memory resident object.
224 * XXX Pointer arithmetic is done with this, so it can't be void *
225 * under "true" ANSI compilers.
227 typedef char *Pointer;
231 * Signed integer, EXACTLY N BITS IN SIZE,
232 * used for numerical computations and the
233 * frontend/backend protocol.
236 typedef signed char int8; /* == 8 bits */
237 typedef signed short int16; /* == 16 bits */
238 typedef signed int int32; /* == 32 bits */
239 #endif /* not HAVE_INT8 */
243 * Unsigned integer, EXACTLY N BITS IN SIZE,
244 * used for numerical computations and the
245 * frontend/backend protocol.
248 typedef unsigned char uint8; /* == 8 bits */
249 typedef unsigned short uint16; /* == 16 bits */
250 typedef unsigned int uint32; /* == 32 bits */
251 #endif /* not HAVE_UINT8 */
255 * Unit of bitwise operation, AT LEAST N BITS IN SIZE.
257 typedef uint8 bits8; /* >= 8 bits */
258 typedef uint16 bits16; /* >= 16 bits */
259 typedef uint32 bits32; /* >= 32 bits */
264 #ifdef HAVE_LONG_INT_64
265 /* Plain "long int" fits, use it */
268 typedef long int int64;
271 typedef unsigned long int uint64;
274 #elif defined(HAVE_LONG_LONG_INT_64)
275 /* We have working support for "long long int", use that */
278 typedef long long int int64;
281 typedef unsigned long long int uint64;
285 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
286 #error must have a working 64-bit integer datatype
289 /* Decide if we need to decorate 64-bit constants */
290 #ifdef HAVE_LL_CONSTANTS
291 #define INT64CONST(x) ((int64) x##LL)
292 #define UINT64CONST(x) ((uint64) x##ULL)
294 #define INT64CONST(x) ((int64) x)
295 #define UINT64CONST(x) ((uint64) x)
299 /* Select timestamp representation (float8 or int64) */
300 #ifdef USE_INTEGER_DATETIMES
301 #define HAVE_INT64_TIMESTAMP
304 /* sig_atomic_t is required by ANSI C, but may be missing on old platforms */
305 #ifndef HAVE_SIG_ATOMIC_T
306 typedef int sig_atomic_t;
311 * Size of any memory resident object, as returned by sizeof.
317 * Index into any memory resident array.
320 * Indices are non negative.
322 typedef unsigned int Index;
326 * Offset into any memory resident array.
329 * This differs from an Index in that an Index is always
330 * non negative, whereas Offset may be negative.
332 typedef signed int Offset;
335 * Common Postgres datatype names (as used in the catalogs)
339 typedef float float4;
340 typedef double float8;
343 * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
347 /* typedef Oid is in postgres_ext.h */
350 * regproc is the type name used in the include/catalog headers, but
351 * RegProcedure is the preferred name in C code.
354 typedef regproc RegProcedure;
356 typedef uint32 TransactionId;
358 typedef uint32 LocalTransactionId;
360 typedef uint32 SubTransactionId;
362 #define InvalidSubTransactionId ((SubTransactionId) 0)
363 #define TopSubTransactionId ((SubTransactionId) 1)
365 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
366 typedef TransactionId MultiXactId;
368 typedef uint32 MultiXactOffset;
370 typedef uint32 CommandId;
372 #define FirstCommandId ((CommandId) 0)
375 * Array indexing support
384 * Variable-length datatypes all share the 'struct varlena' header.
386 * NOTE: for TOASTable types, this is an oversimplification, since the value
387 * may be compressed or moved out-of-line. However datatype-specific routines
388 * are mostly content to deal with de-TOASTed values only, and of course
389 * client-side routines should never see a TOASTed value. But even in a
390 * de-TOASTed value, beware of touching vl_len_ directly, as its representation
391 * is no longer convenient. It's recommended that code always use the VARDATA,
392 * VARSIZE, and SET_VARSIZE macros instead of relying on direct mentions of
393 * the struct fields. See postgres.h for details of the TOASTed form.
398 char vl_len_[4]; /* Do not touch this field directly! */
402 #define VARHDRSZ ((int32) sizeof(int32))
405 * These widely-used datatypes are just a varlena header and the data bytes.
406 * There is no terminating null or anything like that --- the data length is
407 * always VARSIZE(ptr) - VARHDRSZ.
409 typedef struct varlena bytea;
410 typedef struct varlena text;
411 typedef struct varlena BpChar; /* blank-padded char, ie SQL char(n) */
412 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
415 * Specialized array types. These are physically laid out just the same
416 * as regular arrays (so that the regular array subscripting code works
417 * with them). They exist as distinct types mostly for historical reasons:
418 * they have nonstandard I/O behavior which we don't want to change for fear
419 * of breaking applications that look at the system catalogs. There is also
420 * an implementation issue for oidvector: it's part of the primary key for
421 * pg_proc, and we can't use the normal btree array support routines for that
422 * without circularity.
426 int32 vl_len_; /* these fields must match ArrayType! */
427 int ndim; /* always 1 for int2vector */
428 int32 dataoffset; /* always 0 for int2vector */
432 int2 values[1]; /* VARIABLE LENGTH ARRAY */
433 } int2vector; /* VARIABLE LENGTH STRUCT */
437 int32 vl_len_; /* these fields must match ArrayType! */
438 int ndim; /* always 1 for oidvector */
439 int32 dataoffset; /* always 0 for oidvector */
443 Oid values[1]; /* VARIABLE LENGTH ARRAY */
444 } oidvector; /* VARIABLE LENGTH STRUCT */
447 * Representation of a Name: effectively just a C string, but null-padded to
448 * exactly NAMEDATALEN bytes. The use of a struct is historical.
450 typedef struct nameData
452 char data[NAMEDATALEN];
454 typedef NameData *Name;
456 #define NameStr(name) ((name).data)
459 * Support macros for escaping strings. escape_backslash should be TRUE
460 * if generating a non-standard-conforming string. Prefixing a string
461 * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
462 * Beware of multiple evaluation of the "ch" argument!
464 #define SQL_STR_DOUBLE(ch, escape_backslash) \
465 ((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
467 #define ESCAPE_STRING_SYNTAX 'E'
469 /* ----------------------------------------------------------------
470 * Section 4: IsValid macros for system types
471 * ----------------------------------------------------------------
475 * True iff bool is valid.
477 #define BoolIsValid(boolean) ((boolean) == false || (boolean) == true)
481 * True iff pointer is valid.
483 #define PointerIsValid(pointer) ((void*)(pointer) != NULL)
487 * True iff pointer is properly aligned to point to the given type.
489 #define PointerIsAligned(pointer, type) \
490 (((intptr_t)(pointer) % (sizeof (type))) == 0)
492 #define OidIsValid(objectId) ((bool) ((objectId) != InvalidOid))
494 #define RegProcedureIsValid(p) OidIsValid(p)
497 /* ----------------------------------------------------------------
498 * Section 5: offsetof, lengthof, endof, alignment
499 * ----------------------------------------------------------------
503 * Offset of a structure/union field within that structure/union.
505 * XXX This is supposed to be part of stddef.h, but isn't on
506 * some systems (like SunOS 4).
509 #define offsetof(type, field) ((long) &((type *)0)->field)
510 #endif /* offsetof */
514 * Number of elements in an array.
516 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
520 * Address of the element one past the last in an array.
522 #define endof(array) (&(array)[lengthof(array)])
525 * Alignment macros: align a length or address appropriately for a given type.
526 * The fooALIGN() macros round up to a multiple of the required alignment,
527 * while the fooALIGN_DOWN() macros round down. The latter are more useful
528 * for problems like "how many X-sized structures will fit in a page?".
530 * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
531 * That case seems extremely unlikely to be needed in practice, however.
535 #define TYPEALIGN(ALIGNVAL,LEN) \
536 (((intptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((intptr_t) ((ALIGNVAL) - 1)))
538 #define SHORTALIGN(LEN) TYPEALIGN(ALIGNOF_SHORT, (LEN))
539 #define INTALIGN(LEN) TYPEALIGN(ALIGNOF_INT, (LEN))
540 #define LONGALIGN(LEN) TYPEALIGN(ALIGNOF_LONG, (LEN))
541 #define DOUBLEALIGN(LEN) TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
542 #define MAXALIGN(LEN) TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
543 /* MAXALIGN covers only built-in types, not buffers */
544 #define BUFFERALIGN(LEN) TYPEALIGN(ALIGNOF_BUFFER, (LEN))
546 #define TYPEALIGN_DOWN(ALIGNVAL,LEN) \
547 (((intptr_t) (LEN)) & ~((intptr_t) ((ALIGNVAL) - 1)))
549 #define SHORTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
550 #define INTALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
551 #define LONGALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
552 #define DOUBLEALIGN_DOWN(LEN) TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
553 #define MAXALIGN_DOWN(LEN) TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
555 /* ----------------------------------------------------------------
556 * Section 6: widely useful macros
557 * ----------------------------------------------------------------
561 * Return the maximum of two numbers.
563 #define Max(x, y) ((x) > (y) ? (x) : (y))
567 * Return the minimum of two numbers.
569 #define Min(x, y) ((x) < (y) ? (x) : (y))
573 * Return the absolute value of the argument.
575 #define Abs(x) ((x) >= 0 ? (x) : -(x))
579 * Like standard library function strncpy(), except that result string
580 * is guaranteed to be null-terminated --- that is, at most N-1 bytes
581 * of the source string will be kept.
582 * Also, the macro returns no result (too hard to do that without
583 * evaluating the arguments multiple times, which seems worse).
585 * BTW: when you need to copy a non-null-terminated string (like a text
586 * datum) and add a null, do not do it with StrNCpy(..., len+1). That
587 * might seem to work, but it fetches one byte more than there is in the
588 * text object. One fine day you'll have a SIGSEGV because there isn't
589 * another byte before the end of memory. Don't laugh, we've had real
590 * live bug reports from real live users over exactly this mistake.
591 * Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
593 #define StrNCpy(dst,src,len) \
596 char * _dst = (dst); \
601 strncpy(_dst, (src), _len); \
602 _dst[_len-1] = '\0'; \
607 /* Get a bit mask of the bits set in non-long aligned addresses */
608 #define LONG_ALIGN_MASK (sizeof(long) - 1)
612 * Exactly the same as standard library function memset(), but considerably
613 * faster for zeroing small word-aligned structures (such as parsetree nodes).
614 * This has to be a macro because the main point is to avoid function-call
615 * overhead. However, we have also found that the loop is faster than
616 * native libc memset() on some platforms, even those with assembler
617 * memset() functions. More research needs to be done, perhaps with
618 * MEMSET_LOOP_LIMIT tests in configure.
620 #define MemSet(start, val, len) \
623 /* must be void* because we don't know if it is integer aligned yet */ \
624 void *_vstart = (void *) (start); \
628 if ((((intptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
629 (_len & LONG_ALIGN_MASK) == 0 && \
631 _len <= MEMSET_LOOP_LIMIT && \
633 * If MEMSET_LOOP_LIMIT == 0, optimizer should find \
634 * the whole "if" false at compile time. \
636 MEMSET_LOOP_LIMIT != 0) \
638 long *_start = (long *) _vstart; \
639 long *_stop = (long *) ((char *) _start + _len); \
640 while (_start < _stop) \
644 memset(_vstart, _val, _len); \
648 * MemSetAligned is the same as MemSet except it omits the test to see if
649 * "start" is word-aligned. This is okay to use if the caller knows a-priori
650 * that the pointer is suitably aligned (typically, because he just got it
651 * from palloc(), which always delivers a max-aligned pointer).
653 #define MemSetAligned(start, val, len) \
656 long *_start = (long *) (start); \
660 if ((_len & LONG_ALIGN_MASK) == 0 && \
662 _len <= MEMSET_LOOP_LIMIT && \
663 MEMSET_LOOP_LIMIT != 0) \
665 long *_stop = (long *) ((char *) _start + _len); \
666 while (_start < _stop) \
670 memset(_start, _val, _len); \
675 * MemSetTest/MemSetLoop are a variant version that allow all the tests in
676 * MemSet to be done at compile time in cases where "val" and "len" are
677 * constants *and* we know the "start" pointer must be word-aligned.
678 * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
679 * MemSetAligned. Beware of multiple evaluations of the arguments when using
682 #define MemSetTest(val, len) \
683 ( ((len) & LONG_ALIGN_MASK) == 0 && \
684 (len) <= MEMSET_LOOP_LIMIT && \
685 MEMSET_LOOP_LIMIT != 0 && \
688 #define MemSetLoop(start, val, len) \
691 long * _start = (long *) (start); \
692 long * _stop = (long *) ((char *) _start + (Size) (len)); \
694 while (_start < _stop) \
699 /* ----------------------------------------------------------------
700 * Section 7: random stuff
701 * ----------------------------------------------------------------
705 #define HIGHBIT (0x80)
706 #define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)
708 #define STATUS_OK (0)
709 #define STATUS_ERROR (-1)
710 #define STATUS_EOF (-2)
711 #define STATUS_FOUND (1)
712 #define STATUS_WAITING (2)
715 /* gettext domain name mangling */
718 * To better support parallel installations of major PostgeSQL
719 * versions as well as parallel installations of major library soname
720 * versions, we mangle the gettext domain name by appending those
721 * version numbers. The coding rule ought to be that whereever the
722 * domain name is mentioned as a literal, it must be wrapped into
723 * PG_TEXTDOMAIN(). The macros below do not work on non-literals; but
724 * that is somewhat intentional because it avoids having to worry
725 * about multiple states of premangling and postmangling as the values
726 * are being passed around.
728 * Make sure this matches the installation rules in nls-global.mk.
731 /* need a second indirection because we want to stringize the macro value, not the name */
732 #define CppAsString2(x) CppAsString(x)
734 #ifdef SO_MAJOR_VERSION
735 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
737 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
741 /* ----------------------------------------------------------------
742 * Section 8: system-specific hacks
744 * This should be limited to things that absolutely have to be
745 * included in every source file. The port-specific header file
746 * is usually a better place for this sort of thing.
747 * ----------------------------------------------------------------
751 * NOTE: this is also used for opening text files.
752 * WIN32 treats Control-Z as EOF in files opened in text mode.
753 * Therefore, we open files in binary mode on Win32 so we can read
754 * literal control-Z. The other affect is that we see CRLF, but
755 * that is OK because we can already handle those cleanly.
757 #if defined(WIN32) || defined(__CYGWIN__)
758 #define PG_BINARY O_BINARY
759 #define PG_BINARY_A "ab"
760 #define PG_BINARY_R "rb"
761 #define PG_BINARY_W "wb"
764 #define PG_BINARY_A "a"
765 #define PG_BINARY_R "r"
766 #define PG_BINARY_W "w"
770 * Provide prototypes for routines not present in a particular machine's
771 * standard C library.
774 #if !HAVE_DECL_SNPRINTF
776 snprintf(char *str, size_t count, const char *fmt,...)
777 /* This extension allows gcc to check the format string */
778 __attribute__((format(printf, 3, 4)));
781 #if !HAVE_DECL_VSNPRINTF
782 extern int vsnprintf(char *str, size_t count, const char *fmt, va_list args);
785 #if !defined(HAVE_MEMMOVE) && !defined(memmove)
786 #define memmove(d, s, c) bcopy(s, d, c)
790 #define PGDLLIMPORT /* no special DLL markers on most ports */
794 * The following is used as the arg list for signal handlers. Any ports
795 * that take something other than an int argument should override this in
796 * their pg_config_os.h file. Note that variable names are required
797 * because it is used in both the prototypes as well as the definitions.
798 * Note also the long name. We expect that this won't collide with
799 * other names causing compiler warnings.
803 #define SIGNAL_ARGS int postgres_signal_arg
807 * When there is no sigsetjmp, its functionality is provided by plain
808 * setjmp. Incidentally, nothing provides setjmp's functionality in
811 #ifndef HAVE_SIGSETJMP
812 #define sigjmp_buf jmp_buf
813 #define sigsetjmp(x,y) setjmp(x)
814 #define siglongjmp longjmp
817 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
818 extern int fdatasync(int fildes);
821 /* If strtoq() exists, rename it to the more standard strtoll() */
822 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
823 #define strtoll strtoq
824 #define HAVE_STRTOLL 1
827 /* If strtouq() exists, rename it to the more standard strtoull() */
828 #if defined(HAVE_LONG_LONG_INT_64) && !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
829 #define strtoull strtouq
830 #define HAVE_STRTOULL 1
834 * We assume if we have these two functions, we have their friends too, and
835 * can use the wide-character functions.
837 #if defined(HAVE_WCSTOMBS) && defined(HAVE_TOWLOWER)
838 #define USE_WIDE_UPPER_LOWER
841 /* EXEC_BACKEND defines */
843 #define NON_EXEC_STATIC
845 #define NON_EXEC_STATIC static
848 /* /port compatibility functions */