1 /*-------------------------------------------------------------------------
2  *
3  * c.h
4  *	  Fundamental C definitions.  This is included by every .c file in
5  *	  PostgreSQL (via either postgres.h or postgres_fe.h, as appropriate).
6  *
7  *	  Note that the definitions here are not intended to be exposed to clients
8  *	  of the frontend interface libraries --- so we don't worry much about
9  *	  polluting the namespace with lots of stuff...
10  *
11  *
12  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
13  * Portions Copyright (c) 1994, Regents of the University of California
14  *
15  * src/include/c.h
16  *
17  *-------------------------------------------------------------------------
18  */
19 /*
20  *----------------------------------------------------------------
21  *	 TABLE OF CONTENTS
22  *
23  *		When adding stuff to this file, please try to put stuff
24  *		into the relevant section, or add new sections as appropriate.
25  *
26  *	  section	description
27  *	  -------	------------------------------------------------
28  *		0)		pg_config.h and standard system headers
29  *		1)		compiler characteristics
30  *		2)		bool, true, false
31  *		3)		standard system types
32  *		4)		IsValid macros for system types
33  *		5)		offsetof, lengthof, alignment
34  *		6)		assertions
35  *		7)		widely useful macros
36  *		8)		random stuff
37  *		9)		system-specific hacks
38  *
39  * NOTE: since this file is included by both frontend and backend modules,
40  * it's usually wrong to put an "extern" declaration here, unless it's
41  * ifdef'd so that it's seen in only one case or the other.
42  * typedefs and macros are the kind of thing that might go here.
43  *
44  *----------------------------------------------------------------
45  */
46 #ifndef C_H
47 #define C_H
48 
49 #include "postgres_ext.h"
50 
51 /* Must undef pg_config_ext.h symbols before including pg_config.h */
52 #undef PG_INT64_TYPE
53 
54 #include "pg_config.h"
55 #include "pg_config_manual.h"	/* must be after pg_config.h */
56 #include "pg_config_os.h"		/* must be before any system header files */
57 
58 /* System header files that should be available everywhere in Postgres */
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <stddef.h>
63 #include <stdarg.h>
64 #ifdef HAVE_STRINGS_H
65 #include <strings.h>
66 #endif
67 #include <stdint.h>
68 #include <sys/types.h>
69 #include <errno.h>
70 #if defined(WIN32) || defined(__CYGWIN__)
71 #include <fcntl.h>				/* ensure O_BINARY is available */
72 #endif
73 #include <locale.h>
74 #ifdef ENABLE_NLS
75 #include <libintl.h>
76 #endif
77 
78 
79 /* ----------------------------------------------------------------
80  *				Section 1: compiler characteristics
81  *
82  * type prefixes (const, signed, volatile, inline) are handled in pg_config.h.
83  * ----------------------------------------------------------------
84  */
85 
86 /*
87  * Disable "inline" if PG_FORCE_DISABLE_INLINE is defined.
88  * This is used to work around compiler bugs and might also be useful for
89  * investigatory purposes.
90  */
91 #ifdef PG_FORCE_DISABLE_INLINE
92 #undef inline
93 #define inline
94 #endif
95 
96 /*
97  * Attribute macros
98  *
99  * GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
100  * GCC: https://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html
101  * Clang: https://clang.llvm.org/docs/AttributeReference.html
102  * Sunpro: https://docs.oracle.com/cd/E18659_01/html/821-1384/gjzke.html
103  * XLC: https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.2/com.ibm.xlc131.aix.doc/language_ref/function_attributes.html
104  * XLC: https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.2/com.ibm.xlc131.aix.doc/language_ref/type_attrib.html
105  */
106 
107 /*
108  * For compilers which don't support __has_attribute, we just define
109  * __has_attribute(x) to 0 so that we can define macros for various
110  * __attribute__s more easily below.
111  */
112 #ifndef __has_attribute
113 #define __has_attribute(attribute) 0
114 #endif
115 
116 /* only GCC supports the unused attribute */
117 #ifdef __GNUC__
118 #define pg_attribute_unused() __attribute__((unused))
119 #else
120 #define pg_attribute_unused()
121 #endif
122 
123 /*
124  * pg_nodiscard means the compiler should warn if the result of a function
125  * call is ignored.  The name "nodiscard" is chosen in alignment with
126  * (possibly future) C and C++ standards.  For maximum compatibility, use it
127  * as a function declaration specifier, so it goes before the return type.
128  */
129 #ifdef __GNUC__
130 #define pg_nodiscard __attribute__((warn_unused_result))
131 #else
132 #define pg_nodiscard
133 #endif
134 
135 /*
136  * Place this macro before functions that should be allowed to make misaligned
137  * accesses.  Think twice before using it on non-x86-specific code!
138  * Testing can be done with "-fsanitize=alignment -fsanitize-trap=alignment"
139  * on clang, or "-fsanitize=alignment -fno-sanitize-recover=alignment" on gcc.
140  */
141 #if __clang_major__ >= 7 || __GNUC__ >= 8
142 #define pg_attribute_no_sanitize_alignment() __attribute__((no_sanitize("alignment")))
143 #else
144 #define pg_attribute_no_sanitize_alignment()
145 #endif
146 
147 /*
148  * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
149  * used in assert-enabled builds, to avoid compiler warnings about unused
150  * variables in assert-disabled builds.
151  */
152 #ifdef USE_ASSERT_CHECKING
153 #define PG_USED_FOR_ASSERTS_ONLY
154 #else
155 #define PG_USED_FOR_ASSERTS_ONLY pg_attribute_unused()
156 #endif
157 
158 /* GCC and XLC support format attributes */
159 #if defined(__GNUC__) || defined(__IBMC__)
160 #define pg_attribute_format_arg(a) __attribute__((format_arg(a)))
161 #define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a)))
162 #else
163 #define pg_attribute_format_arg(a)
164 #define pg_attribute_printf(f,a)
165 #endif
166 
167 /* GCC, Sunpro and XLC support aligned, packed and noreturn */
168 #if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
169 #define pg_attribute_aligned(a) __attribute__((aligned(a)))
170 #define pg_attribute_noreturn() __attribute__((noreturn))
171 #define pg_attribute_packed() __attribute__((packed))
172 #define HAVE_PG_ATTRIBUTE_NORETURN 1
173 #else
174 /*
175  * NB: aligned and packed are not given default definitions because they
176  * affect code functionality; they *must* be implemented by the compiler
177  * if they are to be used.
178  */
179 #define pg_attribute_noreturn()
180 #endif
181 
182 /*
183  * Use "pg_attribute_always_inline" in place of "inline" for functions that
184  * we wish to force inlining of, even when the compiler's heuristics would
185  * choose not to.  But, if possible, don't force inlining in unoptimized
186  * debug builds.
187  */
188 #if (defined(__GNUC__) && __GNUC__ > 3 && defined(__OPTIMIZE__)) || defined(__SUNPRO_C) || defined(__IBMC__)
189 /* GCC > 3, Sunpro and XLC support always_inline via __attribute__ */
190 #define pg_attribute_always_inline __attribute__((always_inline)) inline
191 #elif defined(_MSC_VER)
192 /* MSVC has a special keyword for this */
193 #define pg_attribute_always_inline __forceinline
194 #else
195 /* Otherwise, the best we can do is to say "inline" */
196 #define pg_attribute_always_inline inline
197 #endif
198 
199 /*
200  * Forcing a function not to be inlined can be useful if it's the slow path of
201  * a performance-critical function, or should be visible in profiles to allow
202  * for proper cost attribution.  Note that unlike the pg_attribute_XXX macros
203  * above, this should be placed before the function's return type and name.
204  */
205 /* GCC, Sunpro and XLC support noinline via __attribute__ */
206 #if (defined(__GNUC__) && __GNUC__ > 2) || defined(__SUNPRO_C) || defined(__IBMC__)
207 #define pg_noinline __attribute__((noinline))
208 /* msvc via declspec */
209 #elif defined(_MSC_VER)
210 #define pg_noinline __declspec(noinline)
211 #else
212 #define pg_noinline
213 #endif
214 
215 /*
216  * For now, just define pg_attribute_cold and pg_attribute_hot to be empty
217  * macros on minGW 8.1.  There appears to be a compiler bug that results in
218  * compilation failure.  At this time, we still have at least one buildfarm
219  * animal running that compiler, so this should make that green again. It's
220  * likely this compiler is not popular enough to warrant keeping this code
221  * around forever, so let's just remove it once the last buildfarm animal
222  * upgrades.
223  */
224 #if defined(__MINGW64__) && __GNUC__ == 8 && __GNUC_MINOR__ == 1
225 
226 #define pg_attribute_cold
227 #define pg_attribute_hot
228 
229 #else
230 /*
231  * Marking certain functions as "hot" or "cold" can be useful to assist the
232  * compiler in arranging the assembly code in a more efficient way.
233  */
234 #if __has_attribute (cold)
235 #define pg_attribute_cold __attribute__((cold))
236 #else
237 #define pg_attribute_cold
238 #endif
239 
240 #if __has_attribute (hot)
241 #define pg_attribute_hot __attribute__((hot))
242 #else
243 #define pg_attribute_hot
244 #endif
245 
246 #endif							/* defined(__MINGW64__) && __GNUC__ == 8 &&
247 								 * __GNUC_MINOR__ == 1 */
248 /*
249  * Mark a point as unreachable in a portable fashion.  This should preferably
250  * be something that the compiler understands, to aid code generation.
251  * In assert-enabled builds, we prefer abort() for debugging reasons.
252  */
253 #if defined(HAVE__BUILTIN_UNREACHABLE) && !defined(USE_ASSERT_CHECKING)
254 #define pg_unreachable() __builtin_unreachable()
255 #elif defined(_MSC_VER) && !defined(USE_ASSERT_CHECKING)
256 #define pg_unreachable() __assume(0)
257 #else
258 #define pg_unreachable() abort()
259 #endif
260 
261 /*
262  * Hints to the compiler about the likelihood of a branch. Both likely() and
263  * unlikely() return the boolean value of the contained expression.
264  *
265  * These should only be used sparingly, in very hot code paths. It's very easy
266  * to mis-estimate likelihoods.
267  */
268 #if __GNUC__ >= 3
269 #define likely(x)	__builtin_expect((x) != 0, 1)
270 #define unlikely(x) __builtin_expect((x) != 0, 0)
271 #else
272 #define likely(x)	((x) != 0)
273 #define unlikely(x) ((x) != 0)
274 #endif
275 
276 /*
277  * CppAsString
278  *		Convert the argument to a string, using the C preprocessor.
279  * CppAsString2
280  *		Convert the argument to a string, after one round of macro expansion.
281  * CppConcat
282  *		Concatenate two arguments together, using the C preprocessor.
283  *
284  * Note: There used to be support here for pre-ANSI C compilers that didn't
285  * support # and ##.  Nowadays, these macros are just for clarity and/or
286  * backward compatibility with existing PostgreSQL code.
287  */
288 #define CppAsString(identifier) #identifier
289 #define CppAsString2(x)			CppAsString(x)
290 #define CppConcat(x, y)			x##y
291 
292 /*
293  * VA_ARGS_NARGS
294  *		Returns the number of macro arguments it is passed.
295  *
296  * An empty argument still counts as an argument, so effectively, this is
297  * "one more than the number of commas in the argument list".
298  *
299  * This works for up to 63 arguments.  Internally, VA_ARGS_NARGS_() is passed
300  * 64+N arguments, and the C99 standard only requires macros to allow up to
301  * 127 arguments, so we can't portably go higher.  The implementation is
302  * pretty trivial: VA_ARGS_NARGS_() returns its 64th argument, and we set up
303  * the call so that that is the appropriate one of the list of constants.
304  * This idea is due to Laurent Deniau.
305  */
306 #define VA_ARGS_NARGS(...) \
307 	VA_ARGS_NARGS_(__VA_ARGS__, \
308 				   63,62,61,60,                   \
309 				   59,58,57,56,55,54,53,52,51,50, \
310 				   49,48,47,46,45,44,43,42,41,40, \
311 				   39,38,37,36,35,34,33,32,31,30, \
312 				   29,28,27,26,25,24,23,22,21,20, \
313 				   19,18,17,16,15,14,13,12,11,10, \
314 				   9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
315 #define VA_ARGS_NARGS_( \
316 	_01,_02,_03,_04,_05,_06,_07,_08,_09,_10, \
317 	_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \
318 	_21,_22,_23,_24,_25,_26,_27,_28,_29,_30, \
319 	_31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \
320 	_41,_42,_43,_44,_45,_46,_47,_48,_49,_50, \
321 	_51,_52,_53,_54,_55,_56,_57,_58,_59,_60, \
322 	_61,_62,_63,  N, ...) \
323 	(N)
324 
325 /*
326  * dummyret is used to set return values in macros that use ?: to make
327  * assignments.  gcc wants these to be void, other compilers like char
328  */
329 #ifdef __GNUC__					/* GNU cc */
330 #define dummyret	void
331 #else
332 #define dummyret	char
333 #endif
334 
335 /*
336  * Generic function pointer.  This can be used in the rare cases where it's
337  * necessary to cast a function pointer to a seemingly incompatible function
338  * pointer type while avoiding gcc's -Wcast-function-type warnings.
339  */
340 typedef void (*pg_funcptr_t) (void);
341 
342 /*
343  * We require C99, hence the compiler should understand flexible array
344  * members.  However, for documentation purposes we still consider it to be
345  * project style to write "field[FLEXIBLE_ARRAY_MEMBER]" not just "field[]".
346  * When computing the size of such an object, use "offsetof(struct s, f)"
347  * for portability.  Don't use "offsetof(struct s, f[0])", as this doesn't
348  * work with MSVC and with C++ compilers.
349  */
350 #define FLEXIBLE_ARRAY_MEMBER	/* empty */
351 
352 /* Which __func__ symbol do we have, if any? */
353 #ifdef HAVE_FUNCNAME__FUNC
354 #define PG_FUNCNAME_MACRO	__func__
355 #else
356 #ifdef HAVE_FUNCNAME__FUNCTION
357 #define PG_FUNCNAME_MACRO	__FUNCTION__
358 #else
359 #define PG_FUNCNAME_MACRO	NULL
360 #endif
361 #endif
362 
363 
364 /* ----------------------------------------------------------------
365  *				Section 2:	bool, true, false
366  * ----------------------------------------------------------------
367  */
368 
369 /*
370  * bool
371  *		Boolean value, either true or false.
372  *
373  * We use stdbool.h if available and its bool has size 1.  That's useful for
374  * better compiler and debugger output and for compatibility with third-party
375  * libraries.  But PostgreSQL currently cannot deal with bool of other sizes;
376  * there are static assertions around the code to prevent that.
377  *
378  * For C++ compilers, we assume the compiler has a compatible built-in
379  * definition of bool.
380  *
381  * See also the version of this code in src/interfaces/ecpg/include/ecpglib.h.
382  */
383 
384 #ifndef __cplusplus
385 
386 #ifdef PG_USE_STDBOOL
387 #include <stdbool.h>
388 #else
389 
390 #ifndef bool
391 typedef unsigned char bool;
392 #endif
393 
394 #ifndef true
395 #define true	((bool) 1)
396 #endif
397 
398 #ifndef false
399 #define false	((bool) 0)
400 #endif
401 
402 #endif							/* not PG_USE_STDBOOL */
403 #endif							/* not C++ */
404 
405 
406 /* ----------------------------------------------------------------
407  *				Section 3:	standard system types
408  * ----------------------------------------------------------------
409  */
410 
411 /*
412  * Pointer
413  *		Variable holding address of any memory resident object.
414  *
415  *		XXX Pointer arithmetic is done with this, so it can't be void *
416  *		under "true" ANSI compilers.
417  */
418 typedef char *Pointer;
419 
420 /*
421  * intN
422  *		Signed integer, EXACTLY N BITS IN SIZE,
423  *		used for numerical computations and the
424  *		frontend/backend protocol.
425  */
426 #ifndef HAVE_INT8
427 typedef signed char int8;		/* == 8 bits */
428 typedef signed short int16;		/* == 16 bits */
429 typedef signed int int32;		/* == 32 bits */
430 #endif							/* not HAVE_INT8 */
431 
432 /*
433  * uintN
434  *		Unsigned integer, EXACTLY N BITS IN SIZE,
435  *		used for numerical computations and the
436  *		frontend/backend protocol.
437  */
438 #ifndef HAVE_UINT8
439 typedef unsigned char uint8;	/* == 8 bits */
440 typedef unsigned short uint16;	/* == 16 bits */
441 typedef unsigned int uint32;	/* == 32 bits */
442 #endif							/* not HAVE_UINT8 */
443 
444 /*
445  * bitsN
446  *		Unit of bitwise operation, AT LEAST N BITS IN SIZE.
447  */
448 typedef uint8 bits8;			/* >= 8 bits */
449 typedef uint16 bits16;			/* >= 16 bits */
450 typedef uint32 bits32;			/* >= 32 bits */
451 
452 /*
453  * 64-bit integers
454  */
455 #ifdef HAVE_LONG_INT_64
456 /* Plain "long int" fits, use it */
457 
458 #ifndef HAVE_INT64
459 typedef long int int64;
460 #endif
461 #ifndef HAVE_UINT64
462 typedef unsigned long int uint64;
463 #endif
464 #define INT64CONST(x)  (x##L)
465 #define UINT64CONST(x) (x##UL)
466 #elif defined(HAVE_LONG_LONG_INT_64)
467 /* We have working support for "long long int", use that */
468 
469 #ifndef HAVE_INT64
470 typedef long long int int64;
471 #endif
472 #ifndef HAVE_UINT64
473 typedef unsigned long long int uint64;
474 #endif
475 #define INT64CONST(x)  (x##LL)
476 #define UINT64CONST(x) (x##ULL)
477 #else
478 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
479 #error must have a working 64-bit integer datatype
480 #endif
481 
482 /* snprintf format strings to use for 64-bit integers */
483 #define INT64_FORMAT "%" INT64_MODIFIER "d"
484 #define UINT64_FORMAT "%" INT64_MODIFIER "u"
485 
486 /*
487  * 128-bit signed and unsigned integers
488  *		There currently is only limited support for such types.
489  *		E.g. 128bit literals and snprintf are not supported; but math is.
490  *		Also, because we exclude such types when choosing MAXIMUM_ALIGNOF,
491  *		it must be possible to coerce the compiler to allocate them on no
492  *		more than MAXALIGN boundaries.
493  */
494 #if defined(PG_INT128_TYPE)
495 #if defined(pg_attribute_aligned) || ALIGNOF_PG_INT128_TYPE <= MAXIMUM_ALIGNOF
496 #define HAVE_INT128 1
497 
498 typedef PG_INT128_TYPE int128
499 #if defined(pg_attribute_aligned)
500 			pg_attribute_aligned(MAXIMUM_ALIGNOF)
501 #endif
502 		   ;
503 
504 typedef unsigned PG_INT128_TYPE uint128
505 #if defined(pg_attribute_aligned)
506 			pg_attribute_aligned(MAXIMUM_ALIGNOF)
507 #endif
508 		   ;
509 
510 #endif
511 #endif
512 
513 /*
514  * stdint.h limits aren't guaranteed to have compatible types with our fixed
515  * width types. So just define our own.
516  */
517 #define PG_INT8_MIN		(-0x7F-1)
518 #define PG_INT8_MAX		(0x7F)
519 #define PG_UINT8_MAX	(0xFF)
520 #define PG_INT16_MIN	(-0x7FFF-1)
521 #define PG_INT16_MAX	(0x7FFF)
522 #define PG_UINT16_MAX	(0xFFFF)
523 #define PG_INT32_MIN	(-0x7FFFFFFF-1)
524 #define PG_INT32_MAX	(0x7FFFFFFF)
525 #define PG_UINT32_MAX	(0xFFFFFFFFU)
526 #define PG_INT64_MIN	(-INT64CONST(0x7FFFFFFFFFFFFFFF) - 1)
527 #define PG_INT64_MAX	INT64CONST(0x7FFFFFFFFFFFFFFF)
528 #define PG_UINT64_MAX	UINT64CONST(0xFFFFFFFFFFFFFFFF)
529 
530 /*
531  * We now always use int64 timestamps, but keep this symbol defined for the
532  * benefit of external code that might test it.
533  */
534 #define HAVE_INT64_TIMESTAMP
535 
536 /*
537  * Size
538  *		Size of any memory resident object, as returned by sizeof.
539  */
540 typedef size_t Size;
541 
542 /*
543  * Index
544  *		Index into any memory resident array.
545  *
546  * Note:
547  *		Indices are non negative.
548  */
549 typedef unsigned int Index;
550 
551 /*
552  * Offset
553  *		Offset into any memory resident array.
554  *
555  * Note:
556  *		This differs from an Index in that an Index is always
557  *		non negative, whereas Offset may be negative.
558  */
559 typedef signed int Offset;
560 
561 /*
562  * Common Postgres datatype names (as used in the catalogs)
563  */
564 typedef float float4;
565 typedef double float8;
566 
567 #ifdef USE_FLOAT8_BYVAL
568 #define FLOAT8PASSBYVAL true
569 #else
570 #define FLOAT8PASSBYVAL false
571 #endif
572 
573 /*
574  * Oid, RegProcedure, TransactionId, SubTransactionId, MultiXactId,
575  * CommandId
576  */
577 
578 /* typedef Oid is in postgres_ext.h */
579 
580 /*
581  * regproc is the type name used in the include/catalog headers, but
582  * RegProcedure is the preferred name in C code.
583  */
584 typedef Oid regproc;
585 typedef regproc RegProcedure;
586 
587 typedef uint32 TransactionId;
588 
589 typedef uint32 LocalTransactionId;
590 
591 typedef uint32 SubTransactionId;
592 
593 #define InvalidSubTransactionId		((SubTransactionId) 0)
594 #define TopSubTransactionId			((SubTransactionId) 1)
595 
596 /* MultiXactId must be equivalent to TransactionId, to fit in t_xmax */
597 typedef TransactionId MultiXactId;
598 
599 typedef uint32 MultiXactOffset;
600 
601 typedef uint32 CommandId;
602 
603 #define FirstCommandId	((CommandId) 0)
604 #define InvalidCommandId	(~(CommandId)0)
605 
606 
607 /* ----------------
608  *		Variable-length datatypes all share the 'struct varlena' header.
609  *
610  * NOTE: for TOASTable types, this is an oversimplification, since the value
611  * may be compressed or moved out-of-line.  However datatype-specific routines
612  * are mostly content to deal with de-TOASTed values only, and of course
613  * client-side routines should never see a TOASTed value.  But even in a
614  * de-TOASTed value, beware of touching vl_len_ directly, as its
615  * representation is no longer convenient.  It's recommended that code always
616  * use macros VARDATA_ANY, VARSIZE_ANY, VARSIZE_ANY_EXHDR, VARDATA, VARSIZE,
617  * and SET_VARSIZE instead of relying on direct mentions of the struct fields.
618  * See postgres.h for details of the TOASTed form.
619  * ----------------
620  */
621 struct varlena
622 {
623 	char		vl_len_[4];		/* Do not touch this field directly! */
624 	char		vl_dat[FLEXIBLE_ARRAY_MEMBER];	/* Data content is here */
625 };
626 
627 #define VARHDRSZ		((int32) sizeof(int32))
628 
629 /*
630  * These widely-used datatypes are just a varlena header and the data bytes.
631  * There is no terminating null or anything like that --- the data length is
632  * always VARSIZE_ANY_EXHDR(ptr).
633  */
634 typedef struct varlena bytea;
635 typedef struct varlena text;
636 typedef struct varlena BpChar;	/* blank-padded char, ie SQL char(n) */
637 typedef struct varlena VarChar; /* var-length char, ie SQL varchar(n) */
638 
639 /*
640  * Specialized array types.  These are physically laid out just the same
641  * as regular arrays (so that the regular array subscripting code works
642  * with them).  They exist as distinct types mostly for historical reasons:
643  * they have nonstandard I/O behavior which we don't want to change for fear
644  * of breaking applications that look at the system catalogs.  There is also
645  * an implementation issue for oidvector: it's part of the primary key for
646  * pg_proc, and we can't use the normal btree array support routines for that
647  * without circularity.
648  */
649 typedef struct
650 {
651 	int32		vl_len_;		/* these fields must match ArrayType! */
652 	int			ndim;			/* always 1 for int2vector */
653 	int32		dataoffset;		/* always 0 for int2vector */
654 	Oid			elemtype;
655 	int			dim1;
656 	int			lbound1;
657 	int16		values[FLEXIBLE_ARRAY_MEMBER];
658 } int2vector;
659 
660 typedef struct
661 {
662 	int32		vl_len_;		/* these fields must match ArrayType! */
663 	int			ndim;			/* always 1 for oidvector */
664 	int32		dataoffset;		/* always 0 for oidvector */
665 	Oid			elemtype;
666 	int			dim1;
667 	int			lbound1;
668 	Oid			values[FLEXIBLE_ARRAY_MEMBER];
669 } oidvector;
670 
671 /*
672  * Representation of a Name: effectively just a C string, but null-padded to
673  * exactly NAMEDATALEN bytes.  The use of a struct is historical.
674  */
675 typedef struct nameData
676 {
677 	char		data[NAMEDATALEN];
678 } NameData;
679 typedef NameData *Name;
680 
681 #define NameStr(name)	((name).data)
682 
683 
684 /* ----------------------------------------------------------------
685  *				Section 4:	IsValid macros for system types
686  * ----------------------------------------------------------------
687  */
688 /*
689  * BoolIsValid
690  *		True iff bool is valid.
691  */
692 #define BoolIsValid(boolean)	((boolean) == false || (boolean) == true)
693 
694 /*
695  * PointerIsValid
696  *		True iff pointer is valid.
697  */
698 #define PointerIsValid(pointer) ((const void*)(pointer) != NULL)
699 
700 /*
701  * PointerIsAligned
702  *		True iff pointer is properly aligned to point to the given type.
703  */
704 #define PointerIsAligned(pointer, type) \
705 		(((uintptr_t)(pointer) % (sizeof (type))) == 0)
706 
707 #define OffsetToPointer(base, offset) \
708 		((void *)((char *) base + offset))
709 
710 #define OidIsValid(objectId)  ((bool) ((objectId) != InvalidOid))
711 
712 #define RegProcedureIsValid(p)	OidIsValid(p)
713 
714 
715 /* ----------------------------------------------------------------
716  *				Section 5:	offsetof, lengthof, alignment
717  * ----------------------------------------------------------------
718  */
719 /*
720  * offsetof
721  *		Offset of a structure/union field within that structure/union.
722  *
723  *		XXX This is supposed to be part of stddef.h, but isn't on
724  *		some systems (like SunOS 4).
725  */
726 #ifndef offsetof
727 #define offsetof(type, field)	((long) &((type *)0)->field)
728 #endif							/* offsetof */
729 
730 /*
731  * lengthof
732  *		Number of elements in an array.
733  */
734 #define lengthof(array) (sizeof (array) / sizeof ((array)[0]))
735 
736 /* ----------------
737  * Alignment macros: align a length or address appropriately for a given type.
738  * The fooALIGN() macros round up to a multiple of the required alignment,
739  * while the fooALIGN_DOWN() macros round down.  The latter are more useful
740  * for problems like "how many X-sized structures will fit in a page?".
741  *
742  * NOTE: TYPEALIGN[_DOWN] will not work if ALIGNVAL is not a power of 2.
743  * That case seems extremely unlikely to be needed in practice, however.
744  *
745  * NOTE: MAXIMUM_ALIGNOF, and hence MAXALIGN(), intentionally exclude any
746  * larger-than-8-byte types the compiler might have.
747  * ----------------
748  */
749 
750 #define TYPEALIGN(ALIGNVAL,LEN)  \
751 	(((uintptr_t) (LEN) + ((ALIGNVAL) - 1)) & ~((uintptr_t) ((ALIGNVAL) - 1)))
752 
753 #define SHORTALIGN(LEN)			TYPEALIGN(ALIGNOF_SHORT, (LEN))
754 #define INTALIGN(LEN)			TYPEALIGN(ALIGNOF_INT, (LEN))
755 #define LONGALIGN(LEN)			TYPEALIGN(ALIGNOF_LONG, (LEN))
756 #define DOUBLEALIGN(LEN)		TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
757 #define MAXALIGN(LEN)			TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
758 /* MAXALIGN covers only built-in types, not buffers */
759 #define BUFFERALIGN(LEN)		TYPEALIGN(ALIGNOF_BUFFER, (LEN))
760 #define CACHELINEALIGN(LEN)		TYPEALIGN(PG_CACHE_LINE_SIZE, (LEN))
761 
762 #define TYPEALIGN_DOWN(ALIGNVAL,LEN)  \
763 	(((uintptr_t) (LEN)) & ~((uintptr_t) ((ALIGNVAL) - 1)))
764 
765 #define SHORTALIGN_DOWN(LEN)	TYPEALIGN_DOWN(ALIGNOF_SHORT, (LEN))
766 #define INTALIGN_DOWN(LEN)		TYPEALIGN_DOWN(ALIGNOF_INT, (LEN))
767 #define LONGALIGN_DOWN(LEN)		TYPEALIGN_DOWN(ALIGNOF_LONG, (LEN))
768 #define DOUBLEALIGN_DOWN(LEN)	TYPEALIGN_DOWN(ALIGNOF_DOUBLE, (LEN))
769 #define MAXALIGN_DOWN(LEN)		TYPEALIGN_DOWN(MAXIMUM_ALIGNOF, (LEN))
770 #define BUFFERALIGN_DOWN(LEN)	TYPEALIGN_DOWN(ALIGNOF_BUFFER, (LEN))
771 
772 /*
773  * The above macros will not work with types wider than uintptr_t, like with
774  * uint64 on 32-bit platforms.  That's not problem for the usual use where a
775  * pointer or a length is aligned, but for the odd case that you need to
776  * align something (potentially) wider, use TYPEALIGN64.
777  */
778 #define TYPEALIGN64(ALIGNVAL,LEN)  \
779 	(((uint64) (LEN) + ((ALIGNVAL) - 1)) & ~((uint64) ((ALIGNVAL) - 1)))
780 
781 /* we don't currently need wider versions of the other ALIGN macros */
782 #define MAXALIGN64(LEN)			TYPEALIGN64(MAXIMUM_ALIGNOF, (LEN))
783 
784 
785 /* ----------------------------------------------------------------
786  *				Section 6:	assertions
787  * ----------------------------------------------------------------
788  */
789 
790 /*
791  * USE_ASSERT_CHECKING, if defined, turns on all the assertions.
792  * - plai  9/5/90
793  *
794  * It should _NOT_ be defined in releases or in benchmark copies
795  */
796 
797 /*
798  * Assert() can be used in both frontend and backend code. In frontend code it
799  * just calls the standard assert, if it's available. If use of assertions is
800  * not configured, it does nothing.
801  */
802 #ifndef USE_ASSERT_CHECKING
803 
804 #define Assert(condition)	((void)true)
805 #define AssertMacro(condition)	((void)true)
806 #define AssertArg(condition)	((void)true)
807 #define AssertState(condition)	((void)true)
808 #define AssertPointerAlignment(ptr, bndr)	((void)true)
809 #define Trap(condition, errorType)	((void)true)
810 #define TrapMacro(condition, errorType) (true)
811 
812 #elif defined(FRONTEND)
813 
814 #include <assert.h>
815 #define Assert(p) assert(p)
816 #define AssertMacro(p)	((void) assert(p))
817 #define AssertArg(condition) assert(condition)
818 #define AssertState(condition) assert(condition)
819 #define AssertPointerAlignment(ptr, bndr)	((void)true)
820 
821 #else							/* USE_ASSERT_CHECKING && !FRONTEND */
822 
823 /*
824  * Trap
825  *		Generates an exception if the given condition is true.
826  */
827 #define Trap(condition, errorType) \
828 	do { \
829 		if (condition) \
830 			ExceptionalCondition(#condition, (errorType), \
831 								 __FILE__, __LINE__); \
832 	} while (0)
833 
834 /*
835  *	TrapMacro is the same as Trap but it's intended for use in macros:
836  *
837  *		#define foo(x) (AssertMacro(x != 0), bar(x))
838  *
839  *	Isn't CPP fun?
840  */
841 #define TrapMacro(condition, errorType) \
842 	((bool) (! (condition) || \
843 			 (ExceptionalCondition(#condition, (errorType), \
844 								   __FILE__, __LINE__), 0)))
845 
846 #define Assert(condition) \
847 	do { \
848 		if (!(condition)) \
849 			ExceptionalCondition(#condition, "FailedAssertion", \
850 								 __FILE__, __LINE__); \
851 	} while (0)
852 
853 #define AssertMacro(condition) \
854 	((void) ((condition) || \
855 			 (ExceptionalCondition(#condition, "FailedAssertion", \
856 								   __FILE__, __LINE__), 0)))
857 
858 #define AssertArg(condition) \
859 	do { \
860 		if (!(condition)) \
861 			ExceptionalCondition(#condition, "BadArgument", \
862 								 __FILE__, __LINE__); \
863 	} while (0)
864 
865 #define AssertState(condition) \
866 	do { \
867 		if (!(condition)) \
868 			ExceptionalCondition(#condition, "BadState", \
869 								 __FILE__, __LINE__); \
870 	} while (0)
871 
872 /*
873  * Check that `ptr' is `bndr' aligned.
874  */
875 #define AssertPointerAlignment(ptr, bndr) \
876 	Trap(TYPEALIGN(bndr, (uintptr_t)(ptr)) != (uintptr_t)(ptr), \
877 		 "UnalignedPointer")
878 
879 #endif							/* USE_ASSERT_CHECKING && !FRONTEND */
880 
881 /*
882  * ExceptionalCondition is compiled into the backend whether or not
883  * USE_ASSERT_CHECKING is defined, so as to support use of extensions
884  * that are built with that #define with a backend that isn't.  Hence,
885  * we should declare it as long as !FRONTEND.
886  */
887 #ifndef FRONTEND
888 extern void ExceptionalCondition(const char *conditionName,
889 								 const char *errorType,
890 								 const char *fileName, int lineNumber) pg_attribute_noreturn();
891 #endif
892 
893 /*
894  * Macros to support compile-time assertion checks.
895  *
896  * If the "condition" (a compile-time-constant expression) evaluates to false,
897  * throw a compile error using the "errmessage" (a string literal).
898  *
899  * gcc 4.6 and up supports _Static_assert(), but there are bizarre syntactic
900  * placement restrictions.  Macros StaticAssertStmt() and StaticAssertExpr()
901  * make it safe to use as a statement or in an expression, respectively.
902  * The macro StaticAssertDecl() is suitable for use at file scope (outside of
903  * any function).
904  *
905  * Otherwise we fall back on a kluge that assumes the compiler will complain
906  * about a negative width for a struct bit-field.  This will not include a
907  * helpful error message, but it beats not getting an error at all.
908  */
909 #ifndef __cplusplus
910 #ifdef HAVE__STATIC_ASSERT
911 #define StaticAssertStmt(condition, errmessage) \
912 	do { _Static_assert(condition, errmessage); } while(0)
913 #define StaticAssertExpr(condition, errmessage) \
914 	((void) ({ StaticAssertStmt(condition, errmessage); true; }))
915 #define StaticAssertDecl(condition, errmessage) \
916 	_Static_assert(condition, errmessage)
917 #else							/* !HAVE__STATIC_ASSERT */
918 #define StaticAssertStmt(condition, errmessage) \
919 	((void) sizeof(struct { int static_assert_failure : (condition) ? 1 : -1; }))
920 #define StaticAssertExpr(condition, errmessage) \
921 	StaticAssertStmt(condition, errmessage)
922 #define StaticAssertDecl(condition, errmessage) \
923 	extern void static_assert_func(int static_assert_failure[(condition) ? 1 : -1])
924 #endif							/* HAVE__STATIC_ASSERT */
925 #else							/* C++ */
926 #if defined(__cpp_static_assert) && __cpp_static_assert >= 200410
927 #define StaticAssertStmt(condition, errmessage) \
928 	static_assert(condition, errmessage)
929 #define StaticAssertExpr(condition, errmessage) \
930 	({ static_assert(condition, errmessage); })
931 #define StaticAssertDecl(condition, errmessage) \
932 	static_assert(condition, errmessage)
933 #else							/* !__cpp_static_assert */
934 #define StaticAssertStmt(condition, errmessage) \
935 	do { struct static_assert_struct { int static_assert_failure : (condition) ? 1 : -1; }; } while(0)
936 #define StaticAssertExpr(condition, errmessage) \
937 	((void) ({ StaticAssertStmt(condition, errmessage); }))
938 #define StaticAssertDecl(condition, errmessage) \
939 	extern void static_assert_func(int static_assert_failure[(condition) ? 1 : -1])
940 #endif							/* __cpp_static_assert */
941 #endif							/* C++ */
942 
943 
944 /*
945  * Compile-time checks that a variable (or expression) has the specified type.
946  *
947  * AssertVariableIsOfType() can be used as a statement.
948  * AssertVariableIsOfTypeMacro() is intended for use in macros, eg
949  *		#define foo(x) (AssertVariableIsOfTypeMacro(x, int), bar(x))
950  *
951  * If we don't have __builtin_types_compatible_p, we can still assert that
952  * the types have the same size.  This is far from ideal (especially on 32-bit
953  * platforms) but it provides at least some coverage.
954  */
955 #ifdef HAVE__BUILTIN_TYPES_COMPATIBLE_P
956 #define AssertVariableIsOfType(varname, typename) \
957 	StaticAssertStmt(__builtin_types_compatible_p(__typeof__(varname), typename), \
958 	CppAsString(varname) " does not have type " CppAsString(typename))
959 #define AssertVariableIsOfTypeMacro(varname, typename) \
960 	(StaticAssertExpr(__builtin_types_compatible_p(__typeof__(varname), typename), \
961 	 CppAsString(varname) " does not have type " CppAsString(typename)))
962 #else							/* !HAVE__BUILTIN_TYPES_COMPATIBLE_P */
963 #define AssertVariableIsOfType(varname, typename) \
964 	StaticAssertStmt(sizeof(varname) == sizeof(typename), \
965 	CppAsString(varname) " does not have type " CppAsString(typename))
966 #define AssertVariableIsOfTypeMacro(varname, typename) \
967 	(StaticAssertExpr(sizeof(varname) == sizeof(typename), \
968 	 CppAsString(varname) " does not have type " CppAsString(typename)))
969 #endif							/* HAVE__BUILTIN_TYPES_COMPATIBLE_P */
970 
971 
972 /* ----------------------------------------------------------------
973  *				Section 7:	widely useful macros
974  * ----------------------------------------------------------------
975  */
976 /*
977  * Max
978  *		Return the maximum of two numbers.
979  */
980 #define Max(x, y)		((x) > (y) ? (x) : (y))
981 
982 /*
983  * Min
984  *		Return the minimum of two numbers.
985  */
986 #define Min(x, y)		((x) < (y) ? (x) : (y))
987 
988 /*
989  * Abs
990  *		Return the absolute value of the argument.
991  */
992 #define Abs(x)			((x) >= 0 ? (x) : -(x))
993 
994 
995 /* Get a bit mask of the bits set in non-long aligned addresses */
996 #define LONG_ALIGN_MASK (sizeof(long) - 1)
997 
998 /*
999  * MemSet
1000  *	Exactly the same as standard library function memset(), but considerably
1001  *	faster for zeroing small word-aligned structures (such as parsetree nodes).
1002  *	This has to be a macro because the main point is to avoid function-call
1003  *	overhead.   However, we have also found that the loop is faster than
1004  *	native libc memset() on some platforms, even those with assembler
1005  *	memset() functions.  More research needs to be done, perhaps with
1006  *	MEMSET_LOOP_LIMIT tests in configure.
1007  */
1008 #define MemSet(start, val, len) \
1009 	do \
1010 	{ \
1011 		/* must be void* because we don't know if it is integer aligned yet */ \
1012 		void   *_vstart = (void *) (start); \
1013 		int		_val = (val); \
1014 		Size	_len = (len); \
1015 \
1016 		if ((((uintptr_t) _vstart) & LONG_ALIGN_MASK) == 0 && \
1017 			(_len & LONG_ALIGN_MASK) == 0 && \
1018 			_val == 0 && \
1019 			_len <= MEMSET_LOOP_LIMIT && \
1020 			/* \
1021 			 *	If MEMSET_LOOP_LIMIT == 0, optimizer should find \
1022 			 *	the whole "if" false at compile time. \
1023 			 */ \
1024 			MEMSET_LOOP_LIMIT != 0) \
1025 		{ \
1026 			long *_start = (long *) _vstart; \
1027 			long *_stop = (long *) ((char *) _start + _len); \
1028 			while (_start < _stop) \
1029 				*_start++ = 0; \
1030 		} \
1031 		else \
1032 			memset(_vstart, _val, _len); \
1033 	} while (0)
1034 
1035 /*
1036  * MemSetAligned is the same as MemSet except it omits the test to see if
1037  * "start" is word-aligned.  This is okay to use if the caller knows a-priori
1038  * that the pointer is suitably aligned (typically, because he just got it
1039  * from palloc(), which always delivers a max-aligned pointer).
1040  */
1041 #define MemSetAligned(start, val, len) \
1042 	do \
1043 	{ \
1044 		long   *_start = (long *) (start); \
1045 		int		_val = (val); \
1046 		Size	_len = (len); \
1047 \
1048 		if ((_len & LONG_ALIGN_MASK) == 0 && \
1049 			_val == 0 && \
1050 			_len <= MEMSET_LOOP_LIMIT && \
1051 			MEMSET_LOOP_LIMIT != 0) \
1052 		{ \
1053 			long *_stop = (long *) ((char *) _start + _len); \
1054 			while (_start < _stop) \
1055 				*_start++ = 0; \
1056 		} \
1057 		else \
1058 			memset(_start, _val, _len); \
1059 	} while (0)
1060 
1061 
1062 /*
1063  * MemSetTest/MemSetLoop are a variant version that allow all the tests in
1064  * MemSet to be done at compile time in cases where "val" and "len" are
1065  * constants *and* we know the "start" pointer must be word-aligned.
1066  * If MemSetTest succeeds, then it is okay to use MemSetLoop, otherwise use
1067  * MemSetAligned.  Beware of multiple evaluations of the arguments when using
1068  * this approach.
1069  */
1070 #define MemSetTest(val, len) \
1071 	( ((len) & LONG_ALIGN_MASK) == 0 && \
1072 	(len) <= MEMSET_LOOP_LIMIT && \
1073 	MEMSET_LOOP_LIMIT != 0 && \
1074 	(val) == 0 )
1075 
1076 #define MemSetLoop(start, val, len) \
1077 	do \
1078 	{ \
1079 		long * _start = (long *) (start); \
1080 		long * _stop = (long *) ((char *) _start + (Size) (len)); \
1081 	\
1082 		while (_start < _stop) \
1083 			*_start++ = 0; \
1084 	} while (0)
1085 
1086 /*
1087  * Macros for range-checking float values before converting to integer.
1088  * We must be careful here that the boundary values are expressed exactly
1089  * in the float domain.  PG_INTnn_MIN is an exact power of 2, so it will
1090  * be represented exactly; but PG_INTnn_MAX isn't, and might get rounded
1091  * off, so avoid using that.
1092  * The input must be rounded to an integer beforehand, typically with rint(),
1093  * else we might draw the wrong conclusion about close-to-the-limit values.
1094  * These macros will do the right thing for Inf, but not necessarily for NaN,
1095  * so check isnan(num) first if that's a possibility.
1096  */
1097 #define FLOAT4_FITS_IN_INT16(num) \
1098 	((num) >= (float4) PG_INT16_MIN && (num) < -((float4) PG_INT16_MIN))
1099 #define FLOAT4_FITS_IN_INT32(num) \
1100 	((num) >= (float4) PG_INT32_MIN && (num) < -((float4) PG_INT32_MIN))
1101 #define FLOAT4_FITS_IN_INT64(num) \
1102 	((num) >= (float4) PG_INT64_MIN && (num) < -((float4) PG_INT64_MIN))
1103 #define FLOAT8_FITS_IN_INT16(num) \
1104 	((num) >= (float8) PG_INT16_MIN && (num) < -((float8) PG_INT16_MIN))
1105 #define FLOAT8_FITS_IN_INT32(num) \
1106 	((num) >= (float8) PG_INT32_MIN && (num) < -((float8) PG_INT32_MIN))
1107 #define FLOAT8_FITS_IN_INT64(num) \
1108 	((num) >= (float8) PG_INT64_MIN && (num) < -((float8) PG_INT64_MIN))
1109 
1110 
1111 /* ----------------------------------------------------------------
1112  *				Section 8:	random stuff
1113  * ----------------------------------------------------------------
1114  */
1115 
1116 #ifdef HAVE_STRUCT_SOCKADDR_UN
1117 #define HAVE_UNIX_SOCKETS 1
1118 #endif
1119 
1120 /*
1121  * Invert the sign of a qsort-style comparison result, ie, exchange negative
1122  * and positive integer values, being careful not to get the wrong answer
1123  * for INT_MIN.  The argument should be an integral variable.
1124  */
1125 #define INVERT_COMPARE_RESULT(var) \
1126 	((var) = ((var) < 0) ? 1 : -(var))
1127 
1128 /*
1129  * Use this, not "char buf[BLCKSZ]", to declare a field or local variable
1130  * holding a page buffer, if that page might be accessed as a page and not
1131  * just a string of bytes.  Otherwise the variable might be under-aligned,
1132  * causing problems on alignment-picky hardware.  (In some places, we use
1133  * this to declare buffers even though we only pass them to read() and
1134  * write(), because copying to/from aligned buffers is usually faster than
1135  * using unaligned buffers.)  We include both "double" and "int64" in the
1136  * union to ensure that the compiler knows the value must be MAXALIGN'ed
1137  * (cf. configure's computation of MAXIMUM_ALIGNOF).
1138  */
1139 typedef union PGAlignedBlock
1140 {
1141 	char		data[BLCKSZ];
1142 	double		force_align_d;
1143 	int64		force_align_i64;
1144 } PGAlignedBlock;
1145 
1146 /* Same, but for an XLOG_BLCKSZ-sized buffer */
1147 typedef union PGAlignedXLogBlock
1148 {
1149 	char		data[XLOG_BLCKSZ];
1150 	double		force_align_d;
1151 	int64		force_align_i64;
1152 } PGAlignedXLogBlock;
1153 
1154 /* msb for char */
1155 #define HIGHBIT					(0x80)
1156 #define IS_HIGHBIT_SET(ch)		((unsigned char)(ch) & HIGHBIT)
1157 
1158 /*
1159  * Support macros for escaping strings.  escape_backslash should be true
1160  * if generating a non-standard-conforming string.  Prefixing a string
1161  * with ESCAPE_STRING_SYNTAX guarantees it is non-standard-conforming.
1162  * Beware of multiple evaluation of the "ch" argument!
1163  */
1164 #define SQL_STR_DOUBLE(ch, escape_backslash)	\
1165 	((ch) == '\'' || ((ch) == '\\' && (escape_backslash)))
1166 
1167 #define ESCAPE_STRING_SYNTAX	'E'
1168 
1169 
1170 #define STATUS_OK				(0)
1171 #define STATUS_ERROR			(-1)
1172 #define STATUS_EOF				(-2)
1173 
1174 /*
1175  * gettext support
1176  */
1177 
1178 #ifndef ENABLE_NLS
1179 /* stuff we'd otherwise get from <libintl.h> */
1180 #define gettext(x) (x)
1181 #define dgettext(d,x) (x)
1182 #define ngettext(s,p,n) ((n) == 1 ? (s) : (p))
1183 #define dngettext(d,s,p,n) ((n) == 1 ? (s) : (p))
1184 #endif
1185 
1186 #define _(x) gettext(x)
1187 
1188 /*
1189  *	Use this to mark string constants as needing translation at some later
1190  *	time, rather than immediately.  This is useful for cases where you need
1191  *	access to the original string and translated string, and for cases where
1192  *	immediate translation is not possible, like when initializing global
1193  *	variables.
1194  *
1195  *	https://www.gnu.org/software/gettext/manual/html_node/Special-cases.html
1196  */
1197 #define gettext_noop(x) (x)
1198 
1199 /*
1200  * To better support parallel installations of major PostgreSQL
1201  * versions as well as parallel installations of major library soname
1202  * versions, we mangle the gettext domain name by appending those
1203  * version numbers.  The coding rule ought to be that wherever the
1204  * domain name is mentioned as a literal, it must be wrapped into
1205  * PG_TEXTDOMAIN().  The macros below do not work on non-literals; but
1206  * that is somewhat intentional because it avoids having to worry
1207  * about multiple states of premangling and postmangling as the values
1208  * are being passed around.
1209  *
1210  * Make sure this matches the installation rules in nls-global.mk.
1211  */
1212 #ifdef SO_MAJOR_VERSION
1213 #define PG_TEXTDOMAIN(domain) (domain CppAsString2(SO_MAJOR_VERSION) "-" PG_MAJORVERSION)
1214 #else
1215 #define PG_TEXTDOMAIN(domain) (domain "-" PG_MAJORVERSION)
1216 #endif
1217 
1218 /*
1219  * Macro that allows to cast constness and volatile away from an expression, but doesn't
1220  * allow changing the underlying type.  Enforcement of the latter
1221  * currently only works for gcc like compilers.
1222  *
1223  * Please note IT IS NOT SAFE to cast constness away if the result will ever
1224  * be modified (it would be undefined behaviour). Doing so anyway can cause
1225  * compiler misoptimizations or runtime crashes (modifying readonly memory).
1226  * It is only safe to use when the result will not be modified, but API
1227  * design or language restrictions prevent you from declaring that
1228  * (e.g. because a function returns both const and non-const variables).
1229  *
1230  * Note that this only works in function scope, not for global variables (it'd
1231  * be nice, but not trivial, to improve that).
1232  */
1233 #if defined(HAVE__BUILTIN_TYPES_COMPATIBLE_P)
1234 #define unconstify(underlying_type, expr) \
1235 	(StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), const underlying_type), \
1236 					  "wrong cast"), \
1237 	 (underlying_type) (expr))
1238 #define unvolatize(underlying_type, expr) \
1239 	(StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), volatile underlying_type), \
1240 					  "wrong cast"), \
1241 	 (underlying_type) (expr))
1242 #else
1243 #define unconstify(underlying_type, expr) \
1244 	((underlying_type) (expr))
1245 #define unvolatize(underlying_type, expr) \
1246 	((underlying_type) (expr))
1247 #endif
1248 
1249 /* ----------------------------------------------------------------
1250  *				Section 9: system-specific hacks
1251  *
1252  *		This should be limited to things that absolutely have to be
1253  *		included in every source file.  The port-specific header file
1254  *		is usually a better place for this sort of thing.
1255  * ----------------------------------------------------------------
1256  */
1257 
1258 /*
1259  *	NOTE:  this is also used for opening text files.
1260  *	WIN32 treats Control-Z as EOF in files opened in text mode.
1261  *	Therefore, we open files in binary mode on Win32 so we can read
1262  *	literal control-Z.  The other affect is that we see CRLF, but
1263  *	that is OK because we can already handle those cleanly.
1264  */
1265 #if defined(WIN32) || defined(__CYGWIN__)
1266 #define PG_BINARY	O_BINARY
1267 #define PG_BINARY_A "ab"
1268 #define PG_BINARY_R "rb"
1269 #define PG_BINARY_W "wb"
1270 #else
1271 #define PG_BINARY	0
1272 #define PG_BINARY_A "a"
1273 #define PG_BINARY_R "r"
1274 #define PG_BINARY_W "w"
1275 #endif
1276 
1277 /*
1278  * Provide prototypes for routines not present in a particular machine's
1279  * standard C library.
1280  */
1281 
1282 #if defined(HAVE_FDATASYNC) && !HAVE_DECL_FDATASYNC
1283 extern int	fdatasync(int fildes);
1284 #endif
1285 
1286 /* Older platforms may provide strto[u]ll functionality under other names */
1287 #if !defined(HAVE_STRTOLL) && defined(HAVE___STRTOLL)
1288 #define strtoll __strtoll
1289 #define HAVE_STRTOLL 1
1290 #endif
1291 
1292 #if !defined(HAVE_STRTOLL) && defined(HAVE_STRTOQ)
1293 #define strtoll strtoq
1294 #define HAVE_STRTOLL 1
1295 #endif
1296 
1297 #if !defined(HAVE_STRTOULL) && defined(HAVE___STRTOULL)
1298 #define strtoull __strtoull
1299 #define HAVE_STRTOULL 1
1300 #endif
1301 
1302 #if !defined(HAVE_STRTOULL) && defined(HAVE_STRTOUQ)
1303 #define strtoull strtouq
1304 #define HAVE_STRTOULL 1
1305 #endif
1306 
1307 #if defined(HAVE_STRTOLL) && !HAVE_DECL_STRTOLL
1308 extern long long strtoll(const char *str, char **endptr, int base);
1309 #endif
1310 
1311 #if defined(HAVE_STRTOULL) && !HAVE_DECL_STRTOULL
1312 extern unsigned long long strtoull(const char *str, char **endptr, int base);
1313 #endif
1314 
1315 /* no special DLL markers on most ports */
1316 #ifndef PGDLLIMPORT
1317 #define PGDLLIMPORT
1318 #endif
1319 #ifndef PGDLLEXPORT
1320 #define PGDLLEXPORT
1321 #endif
1322 
1323 /*
1324  * The following is used as the arg list for signal handlers.  Any ports
1325  * that take something other than an int argument should override this in
1326  * their pg_config_os.h file.  Note that variable names are required
1327  * because it is used in both the prototypes as well as the definitions.
1328  * Note also the long name.  We expect that this won't collide with
1329  * other names causing compiler warnings.
1330  */
1331 
1332 #ifndef SIGNAL_ARGS
1333 #define SIGNAL_ARGS  int postgres_signal_arg
1334 #endif
1335 
1336 /*
1337  * When there is no sigsetjmp, its functionality is provided by plain
1338  * setjmp.  We now support the case only on Windows.  However, it seems
1339  * that MinGW-64 has some longstanding issues in its setjmp support,
1340  * so on that toolchain we cheat and use gcc's builtins.
1341  */
1342 #ifdef WIN32
1343 #ifdef __MINGW64__
1344 typedef intptr_t sigjmp_buf[5];
1345 #define sigsetjmp(x,y) __builtin_setjmp(x)
1346 #define siglongjmp __builtin_longjmp
1347 #else							/* !__MINGW64__ */
1348 #define sigjmp_buf jmp_buf
1349 #define sigsetjmp(x,y) setjmp(x)
1350 #define siglongjmp longjmp
1351 #endif							/* __MINGW64__ */
1352 #endif							/* WIN32 */
1353 
1354 /* EXEC_BACKEND defines */
1355 #ifdef EXEC_BACKEND
1356 #define NON_EXEC_STATIC
1357 #else
1358 #define NON_EXEC_STATIC static
1359 #endif
1360 
1361 /* /port compatibility functions */
1362 #include "port.h"
1363 
1364 #endif							/* C_H */
1365