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		1	=head1 LIBECB - e-C-Builtins
		2
		3	=head2 ABOUT LIBECB
		4
		5	Libecb is currently a simple header file that doesn't require any
		6	configuration to use or include in your project.
		7
		8	It's part of the e-suite of libraries, other members of which include
		9	libev and libeio.
		10
		11	Its homepage can be found here:
		12
		13	http://software.schmorp.de/pkg/libecb
		14
		15	It mainly provides a number of wrappers around GCC built-ins, together
		16	with replacement functions for other compilers. In addition to this,
		17	it provides a number of other lowlevel C utilities, such as endianness
		18	detection, byte swapping or bit rotations.
		19
		20	Or in other words, things that should be built into any standard C system,
		21	but aren't, implemented as efficient as possible with GCC, and still
		22	correct with other compilers.
		23
		24	More might come.
		25
		26	=head2 ABOUT THE HEADER
		27
		28	At the moment, all you have to do is copy F<ecb.h> somewhere where your
		29	compiler can find it and include it:
		30
		31	#include <ecb.h>
		32
		33	The header should work fine for both C and C++ compilation, and gives you
		34	all of F<inttypes.h> in addition to the ECB symbols.
		35
		36	There are currently no object files to link to - future versions might
		37	come with an (optional) object code library to link against, to reduce
		38	code size or gain access to additional features.
		39
		40	It also currently includes everything from F<inttypes.h>.
		41
		42	=head2 ABOUT THIS MANUAL / CONVENTIONS
		43
		44	This manual mainly describes each (public) function available after
		45	including the F<ecb.h> header. The header might define other symbols than
		46	these, but these are not part of the public API, and not supported in any
		47	way.
		48
		49	When the manual mentions a "function" then this could be defined either as
		50	as inline function, a macro, or an external symbol.
		51
		52	When functions use a concrete standard type, such as C<int> or
		53	C<uint32_t>, then the corresponding function works only with that type. If
		54	only a generic name is used (C<expr>, C<cond>, C<value> and so on), then
		55	the corresponding function relies on C to implement the correct types, and
		56	is usually implemented as a macro. Specifically, a "bool" in this manual
		57	refers to any kind of boolean value, not a specific type.
		58
		59	=head2 TYPES / TYPE SUPPORT
		60
		61	ecb.h makes sure that the following types are defined (in the expected way):
		62
		63	int8_t uint8_t int16_t uint16_t
		64	int32_t uint32_t int64_t uint64_t
		65	intptr_t uintptr_t ptrdiff_t
		66
		67	The macro C<ECB_PTRSIZE> is defined to the size of a pointer on this
		68	platform (currently C<4> or C<8>) and can be used in preprocessor
		69	expressions.
		70
		71	=head2 LANGUAGE/COMPILER VERSIONS
		72
		73	All the following symbols expand to an expression that can be tested in
		74	preprocessor instructions as well as treated as a boolean (use C<!!> to
		75	ensure it's either C<0> or C<1> if you need that).
		76
		77	=over 4
		78
		79	=item ECB_C
		80
		81	True if the implementation defines the C<__STDC__> macro to a true value,
		82	which is typically true for both C and C++ compilers.
		83
		84	=item ECB_C99
		85
		86	True if the implementation claims to be compliant to C99 (ISO/IEC
		87	9899:1999) or any later version.
		88
		89	Note that later versions (ECB_C11) remove core features again (for
		90	example, variable length arrays).
		91
		92	=item ECB_C11
		93
		94	True if the implementation claims to be compliant to C11 (ISO/IEC
		95	9899:2011) or any later version.
		96
		97	=item ECB_CPP
		98
		99	True if the implementation defines the C<__cplusplus__> macro to a true
		100	value, which is typically true for C++ compilers.
		101
		102	=item ECB_CPP98
		103
		104	True if the implementation claims to be compliant to ISO/IEC 14882:1998
		105	(the first C++ ISO standard) or any later version. Typically true for all
		106	C++ compilers.
		107
		108	=item ECB_CPP11
		109
		110	True if the implementation claims to be compliant to ISO/IEC 14882:2011
		111	(C++11) or any later version.
		112
		113	=item ECB_GCC_VERSION(major,minor)
		114
		115	Expands to a true value (suitable for testing in by the preprocessor)
		116	if the compiler used is GNU C and the version is the given version, or
		117	higher.
		118
		119	This macro tries to return false on compilers that claim to be GCC
		120	compatible but aren't.
		121
		122	=back
1		123
2	=head2 GCC ATTRIBUTES	124	=head2 GCC ATTRIBUTES
3		125
		126	A major part of libecb deals with GCC attributes. These are additional
		127	attributes that you can assign to functions, variables and sometimes even
		128	types - much like C<const> or C<volatile> in C.
		129
		130	While GCC allows declarations to show up in many surprising places,
		131	but not in many expected places, the safest way is to put attribute
		132	declarations before the whole declaration:
		133
		134	ecb_const int mysqrt (int a);
		135	ecb_unused int i;
		136
		137	For variables, it is often nicer to put the attribute after the name, and
		138	avoid multiple declarations using commas:
		139
		140	int i ecb_unused;
		141
4	=over 4	142	=over 4
5		143
6	=item ecb_attribute(attrlist)	144	=item ecb_attribute ((attrs...))
7	=item ecb_noinline ecb_attribute ((noinline))
8	=item ecb_noreturn ecb_attribute ((noreturn))
9	=item ecb_unused ecb_attribute ((unused))
10	=item ecb_const ecb_attribute ((const))
11	=item ecb_pure ecb_attribute ((pure))
12	=item ecb_hot ecb_attribute ((hot)) /* 4.3 */
13	=item ecb_cold ecb_attribute ((cold)) /* 4.3 */
14		145
		146	A simple wrapper that expands to C<__attribute__((attrs))> on GCC, and to
		147	nothing on other compilers, so the effect is that only GCC sees these.
		148
		149	Example: use the C<deprecated> attribute on a function.
		150
		151	ecb_attribute((__deprecated__)) void
		152	do_not_use_me_anymore (void);
		153
		154	=item ecb_unused
		155
		156	Marks a function or a variable as "unused", which simply suppresses a
		157	warning by GCC when it detects it as unused. This is useful when you e.g.
		158	declare a variable but do not always use it:
		159
		160	{
		161	int var ecb_unused;
		162
		163	#ifdef SOMECONDITION
		164	var = ...;
		165	return var;
		166	#else
		167	return 0;
		168	#endif
		169	}
		170
		171	=item ecb_inline
		172
		173	This is not actually an attribute, but you use it like one. It expands
		174	either to C<static inline> or to just C<static>, if inline isn't
		175	supported. It should be used to declare functions that should be inlined,
		176	for code size or speed reasons.
		177
		178	Example: inline this function, it surely will reduce codesize.
		179
		180	ecb_inline int
		181	negmul (int a, int b)
		182	{
		183	return - (a * b);
		184	}
		185
		186	=item ecb_noinline
		187
		188	Prevent a function from being inlined - it might be optimised away, but
		189	not inlined into other functions. This is useful if you know your function
		190	is rarely called and large enough for inlining not to be helpful.
		191
		192	=item ecb_noreturn
		193
		194	Marks a function as "not returning, ever". Some typical functions that
		195	don't return are C<exit> or C<abort> (which really works hard to not
		196	return), and now you can make your own:
		197
		198	ecb_noreturn void
		199	my_abort (const char *errline)
		200	{
		201	puts (errline);
		202	abort ();
		203	}
		204
		205	In this case, the compiler would probably be smart enough to deduce it on
		206	its own, so this is mainly useful for declarations.
		207
		208	=item ecb_const
		209
		210	Declares that the function only depends on the values of its arguments,
		211	much like a mathematical function. It specifically does not read or write
		212	any memory any arguments might point to, global variables, or call any
		213	non-const functions. It also must not have any side effects.
		214
		215	Such a function can be optimised much more aggressively by the compiler -
		216	for example, multiple calls with the same arguments can be optimised into
		217	a single call, which wouldn't be possible if the compiler would have to
		218	expect any side effects.
		219
		220	It is best suited for functions in the sense of mathematical functions,
		221	such as a function returning the square root of its input argument.
		222
		223	Not suited would be a function that calculates the hash of some memory
		224	area you pass in, prints some messages or looks at a global variable to
		225	decide on rounding.
		226
		227	See C<ecb_pure> for a slightly less restrictive class of functions.
		228
		229	=item ecb_pure
		230
		231	Similar to C<ecb_const>, declares a function that has no side
		232	effects. Unlike C<ecb_const>, the function is allowed to examine global
		233	variables and any other memory areas (such as the ones passed to it via
		234	pointers).
		235
		236	While these functions cannot be optimised as aggressively as C<ecb_const>
		237	functions, they can still be optimised away in many occasions, and the
		238	compiler has more freedom in moving calls to them around.
		239
		240	Typical examples for such functions would be C<strlen> or C<memcmp>. A
		241	function that calculates the MD5 sum of some input and updates some MD5
		242	state passed as argument would I<NOT> be pure, however, as it would modify
		243	some memory area that is not the return value.
		244
		245	=item ecb_hot
		246
		247	This declares a function as "hot" with regards to the cache - the function
		248	is used so often, that it is very beneficial to keep it in the cache if
		249	possible.
		250
		251	The compiler reacts by trying to place hot functions near to each other in
		252	memory.
		253
		254	Whether a function is hot or not often depends on the whole program,
		255	and less on the function itself. C<ecb_cold> is likely more useful in
		256	practise.
		257
		258	=item ecb_cold
		259
		260	The opposite of C<ecb_hot> - declares a function as "cold" with regards to
		261	the cache, or in other words, this function is not called often, or not at
		262	speed-critical times, and keeping it in the cache might be a waste of said
		263	cache.
		264
		265	In addition to placing cold functions together (or at least away from hot
		266	functions), this knowledge can be used in other ways, for example, the
		267	function will be optimised for size, as opposed to speed, and codepaths
		268	leading to calls to those functions can automatically be marked as if
		269	C<ecb_expect_false> had been used to reach them.
		270
		271	Good examples for such functions would be error reporting functions, or
		272	functions only called in exceptional or rare cases.
		273
		274	=item ecb_artificial
		275
		276	Declares the function as "artificial", in this case meaning that this
		277	function is not really mean to be a function, but more like an accessor
		278	- many methods in C++ classes are mere accessor functions, and having a
		279	crash reported in such a method, or single-stepping through them, is not
		280	usually so helpful, especially when it's inlined to just a few instructions.
		281
		282	Marking them as artificial will instruct the debugger about just this,
		283	leading to happier debugging and thus happier lives.
		284
		285	Example: in some kind of smart-pointer class, mark the pointer accessor as
		286	artificial, so that the whole class acts more like a pointer and less like
		287	some C++ abstraction monster.
		288
		289	template<typename T>
		290	struct my_smart_ptr
		291	{
		292	T *value;
		293
		294	ecb_artificial
		295	operator T *()
		296	{
		297	return value;
		298	}
		299	};
		300
15	=back	301	=back
16		302
17	=head2 OPTIMISATION HINTS	303	=head2 OPTIMISATION HINTS
18		304
19	=over 4	305	=over 4
20		306
21	=item bool ecb_is_constant(expr)	307	=item bool ecb_is_constant(expr)
22		308
		309	Returns true iff the expression can be deduced to be a compile-time
		310	constant, and false otherwise.
		311
		312	For example, when you have a C<rndm16> function that returns a 16 bit
		313	random number, and you have a function that maps this to a range from
		314	0..n-1, then you could use this inline function in a header file:
		315
		316	ecb_inline uint32_t
		317	rndm (uint32_t n)
		318	{
		319	return (n * (uint32_t)rndm16 ()) >> 16;
		320	}
		321
		322	However, for powers of two, you could use a normal mask, but that is only
		323	worth it if, at compile time, you can detect this case. This is the case
		324	when the passed number is a constant and also a power of two (C<n & (n -
		325	1) == 0>):
		326
		327	ecb_inline uint32_t
		328	rndm (uint32_t n)
		329	{
		330	return is_constant (n) && !(n & (n - 1))
		331	? rndm16 () & (num - 1)
		332	: (n * (uint32_t)rndm16 ()) >> 16;
		333	}
		334
23	=item bool ecb_expect(expr,value)	335	=item bool ecb_expect (expr, value)
24		336
25	=item bool ecb_unlikely(bool)	337	Evaluates C<expr> and returns it. In addition, it tells the compiler that
		338	the C<expr> evaluates to C<value> a lot, which can be used for static
		339	branch optimisations.
26		340
27	=item bool ecb_likely(bool)	341	Usually, you want to use the more intuitive C<ecb_expect_true> and
		342	C<ecb_expect_false> functions instead.
28		343
		344	=item bool ecb_expect_true (cond)
		345
		346	=item bool ecb_expect_false (cond)
		347
		348	These two functions expect a expression that is true or false and return
		349	C<1> or C<0>, respectively, so when used in the condition of an C<if> or
		350	other conditional statement, it will not change the program:
		351
		352	/* these two do the same thing */
		353	if (some_condition) ...;
		354	if (ecb_expect_true (some_condition)) ...;
		355
		356	However, by using C<ecb_expect_true>, you tell the compiler that the
		357	condition is likely to be true (and for C<ecb_expect_false>, that it is
		358	unlikely to be true).
		359
		360	For example, when you check for a null pointer and expect this to be a
		361	rare, exceptional, case, then use C<ecb_expect_false>:
		362
		363	void my_free (void *ptr)
		364	{
		365	if (ecb_expect_false (ptr == 0))
		366	return;
		367	}
		368
		369	Consequent use of these functions to mark away exceptional cases or to
		370	tell the compiler what the hot path through a function is can increase
		371	performance considerably.
		372
		373	You might know these functions under the name C<likely> and C<unlikely>
		374	- while these are common aliases, we find that the expect name is easier
		375	to understand when quickly skimming code. If you wish, you can use
		376	C<ecb_likely> instead of C<ecb_expect_true> and C<ecb_unlikely> instead of
		377	C<ecb_expect_false> - these are simply aliases.
		378
		379	A very good example is in a function that reserves more space for some
		380	memory block (for example, inside an implementation of a string stream) -
		381	each time something is added, you have to check for a buffer overrun, but
		382	you expect that most checks will turn out to be false:
		383
		384	/* make sure we have "size" extra room in our buffer */
		385	ecb_inline void
		386	reserve (int size)
		387	{
		388	if (ecb_expect_false (current + size > end))
		389	real_reserve_method (size); /* presumably noinline */
		390	}
		391
29	=item bool ecb_assume(cond)	392	=item bool ecb_assume (cond)
30		393
		394	Try to tell the compiler that some condition is true, even if it's not
		395	obvious.
		396
		397	This can be used to teach the compiler about invariants or other
		398	conditions that might improve code generation, but which are impossible to
		399	deduce form the code itself.
		400
		401	For example, the example reservation function from the C<ecb_expect_false>
		402	description could be written thus (only C<ecb_assume> was added):
		403
		404	ecb_inline void
		405	reserve (int size)
		406	{
		407	if (ecb_expect_false (current + size > end))
		408	real_reserve_method (size); /* presumably noinline */
		409
		410	ecb_assume (current + size <= end);
		411	}
		412
		413	If you then call this function twice, like this:
		414
		415	reserve (10);
		416	reserve (1);
		417
		418	Then the compiler I<might> be able to optimise out the second call
		419	completely, as it knows that C<< current + 1 > end >> is false and the
		420	call will never be executed.
		421
31	=item bool ecb_unreachable()	422	=item bool ecb_unreachable ()
32		423
		424	This function does nothing itself, except tell the compiler that it will
		425	never be executed. Apart from suppressing a warning in some cases, this
		426	function can be used to implement C<ecb_assume> or similar functions.
		427
33	=item bool ecb_prefetch(addr,rw,locality)	428	=item bool ecb_prefetch (addr, rw, locality)
34		429
		430	Tells the compiler to try to prefetch memory at the given C<addr>ess
		431	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of
		432	C<0> means that there will only be one access later, C<3> means that
		433	the data will likely be accessed very often, and values in between mean
		434	something... in between. The memory pointed to by the address does not
		435	need to be accessible (it could be a null pointer for example), but C<rw>
		436	and C<locality> must be compile-time constants.
		437
		438	An obvious way to use this is to prefetch some data far away, in a big
		439	array you loop over. This prefetches memory some 128 array elements later,
		440	in the hope that it will be ready when the CPU arrives at that location.
		441
		442	int sum = 0;
		443
		444	for (i = 0; i < N; ++i)
		445	{
		446	sum += arr [i]
		447	ecb_prefetch (arr + i + 128, 0, 0);
		448	}
		449
		450	It's hard to predict how far to prefetch, and most CPUs that can prefetch
		451	are often good enough to predict this kind of behaviour themselves. It
		452	gets more interesting with linked lists, especially when you do some fair
		453	processing on each list element:
		454
		455	for (node *n = start; n; n = n->next)
		456	{
		457	ecb_prefetch (n->next, 0, 0);
		458	... do medium amount of work with *n
		459	}
		460
		461	After processing the node, (part of) the next node might already be in
		462	cache.
		463
35	=back	464	=back
36		465
37	=head2 BIT FIDDLING / BITSTUFFS	466	=head2 BIT FIDDLING / BIT WIZARDRY
38		467
		468	=over 4
		469
39	bool ecb_big_endian ();	470	=item bool ecb_big_endian ()
		471
40	bool ecb_little_endian ();	472	=item bool ecb_little_endian ()
		473
		474	These two functions return true if the byte order is big endian
		475	(most-significant byte first) or little endian (least-significant byte
		476	first) respectively.
		477
		478	On systems that are neither, their return values are unspecified.
		479
41	int ecb_ctz32 (uint32_t x);	480	=item int ecb_ctz32 (uint32_t x)
		481
		482	=item int ecb_ctz64 (uint64_t x)
		483
		484	Returns the index of the least significant bit set in C<x> (or
		485	equivalently the number of bits set to 0 before the least significant bit
		486	set), starting from 0. If C<x> is 0 the result is undefined.
		487
		488	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
		489
		490	For example:
		491
		492	ecb_ctz32 (3) = 0
		493	ecb_ctz32 (6) = 1
		494
		495	=item bool ecb_is_pot32 (uint32_t x)
		496
		497	=item bool ecb_is_pot64 (uint32_t x)
		498
		499	Return true iff C<x> is a power of two or C<x == 0>.
		500
		501	For smaller types then C<uint32_t> you can safely use C<ecb_is_pot32>.
		502
		503	=item int ecb_ld32 (uint32_t x)
		504
		505	=item int ecb_ld64 (uint64_t x)
		506
		507	Returns the index of the most significant bit set in C<x>, or the number
		508	of digits the number requires in binary (so that C<< 2**ld <= x <
		509	2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
		510	to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
		511	example to see how many bits a certain number requires to be encoded.
		512
		513	This function is similar to the "count leading zero bits" function, except
		514	that that one returns how many zero bits are "in front" of the number (in
		515	the given data type), while C<ecb_ld> returns how many bits the number
		516	itself requires.
		517
		518	For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
		519
42	int ecb_popcount32 (uint32_t x);	520	=item int ecb_popcount32 (uint32_t x)
		521
		522	=item int ecb_popcount64 (uint64_t x)
		523
		524	Returns the number of bits set to 1 in C<x>.
		525
		526	For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
		527
		528	For example:
		529
		530	ecb_popcount32 (7) = 3
		531	ecb_popcount32 (255) = 8
		532
		533	=item uint8_t ecb_bitrev8 (uint8_t x)
		534
		535	=item uint16_t ecb_bitrev16 (uint16_t x)
		536
43	uint32_t ecb_bswap32 (uint32_t x);	537	=item uint32_t ecb_bitrev32 (uint32_t x)
		538
		539	Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
		540	and so on.
		541
		542	Example:
		543
		544	ecb_bitrev8 (0xa7) = 0xea
		545	ecb_bitrev32 (0xffcc4411) = 0x882233ff
		546
44	uint32_t ecb_bswap16 (uint32_t x);	547	=item uint32_t ecb_bswap16 (uint32_t x)
		548
		549	=item uint32_t ecb_bswap32 (uint32_t x)
		550
		551	=item uint64_t ecb_bswap64 (uint64_t x)
		552
		553	These functions return the value of the 16-bit (32-bit, 64-bit) value
		554	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
		555	C<ecb_bswap32>).
		556
45	uint32_t ecb_rotr32 (uint32_t x, unsigned int count);	557	=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
		558
		559	=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
		560
46	uint32_t ecb_rotl32 (uint32_t x, unsigned int count);	561	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)
		562
		563	=item uint64_t ecb_rotl64 (uint64_t x, unsigned int count)
		564
		565	=item uint8_t ecb_rotr8 (uint8_t x, unsigned int count)
		566
		567	=item uint16_t ecb_rotr16 (uint16_t x, unsigned int count)
		568
		569	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)
		570
		571	=item uint64_t ecb_rotr64 (uint64_t x, unsigned int count)
		572
		573	These two families of functions return the value of C<x> after rotating
		574	all the bits by C<count> positions to the right (C<ecb_rotr>) or left
		575	(C<ecb_rotl>).
		576
		577	Current GCC versions understand these functions and usually compile them
		578	to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
		579	x86).
		580
		581	=back
47		582
48	=head2 ARITHMETIC	583	=head2 ARITHMETIC
49		584
		585	=over 4
		586
50	x = ecb_mod (m, n)	587	=item x = ecb_mod (m, n)
		588
		589	Returns C<m> modulo C<n>, which is the same as the positive remainder
		590	of the division operation between C<m> and C<n>, using floored
		591	division. Unlike the C remainder operator C<%>, this function ensures that
		592	the return value is always positive and that the two numbers I<m> and
		593	I<m' = m + i * n> result in the same value modulo I<n> - in other words,
		594	C<ecb_mod> implements the mathematical modulo operation, which is missing
		595	in the language.
		596
		597	C<n> must be strictly positive (i.e. C<< >= 1 >>), while C<m> must be
		598	negatable, that is, both C<m> and C<-m> must be representable in its
		599	type (this typically excludes the minimum signed integer value, the same
		600	limitation as for C</> and C<%> in C).
		601
		602	Current GCC versions compile this into an efficient branchless sequence on
		603	almost all CPUs.
		604
		605	For example, when you want to rotate forward through the members of an
		606	array for increasing C<m> (which might be negative), then you should use
		607	C<ecb_mod>, as the C<%> operator might give either negative results, or
		608	change direction for negative values:
		609
		610	for (m = -100; m <= 100; ++m)
		611	int elem = myarray [ecb_mod (m, ecb_array_length (myarray))];
		612
		613	=item x = ecb_div_rd (val, div)
		614
		615	=item x = ecb_div_ru (val, div)
		616
		617	Returns C<val> divided by C<div> rounded down or up, respectively.
		618	C<val> and C<div> must have integer types and C<div> must be strictly
		619	positive. Note that these functions are implemented with macros in C
		620	and with function templates in C++.
		621
		622	=back
51		623
52	=head2 UTILITY	624	=head2 UTILITY
53		625
54	ecb_array_length (name)	626	=over 4
55		627
		628	=item element_count = ecb_array_length (name)
56		629
		630	Returns the number of elements in the array C<name>. For example:
		631
		632	int primes[] = { 2, 3, 5, 7, 11 };
		633	int sum = 0;
		634
		635	for (i = 0; i < ecb_array_length (primes); i++)
		636	sum += primes [i];
		637
		638	=back
		639
		640	=head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF
		641
		642	These symbols need to be defined before including F<ecb.h> the first time.
		643
		644	=over 4
		645
		646	=item ECB_NO_THRADS
		647
		648	If F<ecb.h> is never used from multiple threads, then this symbol can
		649	be defined, in which case memory fences (and similar constructs) are
		650	completely removed, leading to more efficient code and fewer dependencies.
		651
		652	Setting this symbol to a true value implies C<ECB_NO_SMP>.
		653
		654	=item ECB_NO_SMP
		655
		656	The weaker version of C<ECB_NO_THREADS> - if F<ecb.h> is used from
		657	multiple threads, but never concurrently (e.g. if the system the program
		658	runs on has only a single CPU with a single core, no hyperthreading and so
		659	on), then this symbol can be defined, leading to more efficient code and
		660	fewer dependencies.
		661
		662	=back
		663
		664

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Comparing libecb/ecb.pod (file contents): Revision 1.1 by root, Thu May 26 19:39:40 2011 UTC vs. Revision 1.47 by root, Tue May 29 16:51:24 2012 UTC

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Comparing libecb/ecb.pod (file contents):
Revision 1.1 by root, Thu May 26 19:39:40 2011 UTC vs.
Revision 1.47 by root, Tue May 29 16:51:24 2012 UTC