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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_CPP11
		103
		104	True if the implementation claims to be compliant to ISO/IEC 14882:2011
		105	(C++11) or any later version.
		106
		107	=item ECB_GCC_VERSION(major,minor)
		108
		109	Expands to a true value (suitable for testing in by the preprocessor)
		110	if the compiler used is GNU C and the version is the given version, or
		111	higher.
		112
		113	This macro tries to return false on compilers that claim to be GCC
		114	compatible but aren't.
		115
		116	=back
1		117
2	=head2 GCC ATTRIBUTES	118	=head2 GCC ATTRIBUTES
3		119
		120	A major part of libecb deals with GCC attributes. These are additional
		121	attributes that you can assign to functions, variables and sometimes even
		122	types - much like C<const> or C<volatile> in C.
		123
		124	While GCC allows declarations to show up in many surprising places,
		125	but not in many expected places, the safest way is to put attribute
		126	declarations before the whole declaration:
		127
		128	ecb_const int mysqrt (int a);
		129	ecb_unused int i;
		130
		131	For variables, it is often nicer to put the attribute after the name, and
		132	avoid multiple declarations using commas:
		133
		134	int i ecb_unused;
		135
4	=over 4	136	=over 4
5		137
6	=item ecb_attribute(attrlist)	138	=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		139
		140	A simple wrapper that expands to C<__attribute__((attrs))> on GCC, and to
		141	nothing on other compilers, so the effect is that only GCC sees these.
		142
		143	Example: use the C<deprecated> attribute on a function.
		144
		145	ecb_attribute((__deprecated__)) void
		146	do_not_use_me_anymore (void);
		147
		148	=item ecb_unused
		149
		150	Marks a function or a variable as "unused", which simply suppresses a
		151	warning by GCC when it detects it as unused. This is useful when you e.g.
		152	declare a variable but do not always use it:
		153
		154	{
		155	int var ecb_unused;
		156
		157	#ifdef SOMECONDITION
		158	var = ...;
		159	return var;
		160	#else
		161	return 0;
		162	#endif
		163	}
		164
		165	=item ecb_inline
		166
		167	This is not actually an attribute, but you use it like one. It expands
		168	either to C<static inline> or to just C<static>, if inline isn't
		169	supported. It should be used to declare functions that should be inlined,
		170	for code size or speed reasons.
		171
		172	Example: inline this function, it surely will reduce codesize.
		173
		174	ecb_inline int
		175	negmul (int a, int b)
		176	{
		177	return - (a * b);
		178	}
		179
		180	=item ecb_noinline
		181
		182	Prevent a function from being inlined - it might be optimised away, but
		183	not inlined into other functions. This is useful if you know your function
		184	is rarely called and large enough for inlining not to be helpful.
		185
		186	=item ecb_noreturn
		187
		188	Marks a function as "not returning, ever". Some typical functions that
		189	don't return are C<exit> or C<abort> (which really works hard to not
		190	return), and now you can make your own:
		191
		192	ecb_noreturn void
		193	my_abort (const char *errline)
		194	{
		195	puts (errline);
		196	abort ();
		197	}
		198
		199	In this case, the compiler would probably be smart enough to deduce it on
		200	its own, so this is mainly useful for declarations.
		201
		202	=item ecb_const
		203
		204	Declares that the function only depends on the values of its arguments,
		205	much like a mathematical function. It specifically does not read or write
		206	any memory any arguments might point to, global variables, or call any
		207	non-const functions. It also must not have any side effects.
		208
		209	Such a function can be optimised much more aggressively by the compiler -
		210	for example, multiple calls with the same arguments can be optimised into
		211	a single call, which wouldn't be possible if the compiler would have to
		212	expect any side effects.
		213
		214	It is best suited for functions in the sense of mathematical functions,
		215	such as a function returning the square root of its input argument.
		216
		217	Not suited would be a function that calculates the hash of some memory
		218	area you pass in, prints some messages or looks at a global variable to
		219	decide on rounding.
		220
		221	See C<ecb_pure> for a slightly less restrictive class of functions.
		222
		223	=item ecb_pure
		224
		225	Similar to C<ecb_const>, declares a function that has no side
		226	effects. Unlike C<ecb_const>, the function is allowed to examine global
		227	variables and any other memory areas (such as the ones passed to it via
		228	pointers).
		229
		230	While these functions cannot be optimised as aggressively as C<ecb_const>
		231	functions, they can still be optimised away in many occasions, and the
		232	compiler has more freedom in moving calls to them around.
		233
		234	Typical examples for such functions would be C<strlen> or C<memcmp>. A
		235	function that calculates the MD5 sum of some input and updates some MD5
		236	state passed as argument would I<NOT> be pure, however, as it would modify
		237	some memory area that is not the return value.
		238
		239	=item ecb_hot
		240
		241	This declares a function as "hot" with regards to the cache - the function
		242	is used so often, that it is very beneficial to keep it in the cache if
		243	possible.
		244
		245	The compiler reacts by trying to place hot functions near to each other in
		246	memory.
		247
		248	Whether a function is hot or not often depends on the whole program,
		249	and less on the function itself. C<ecb_cold> is likely more useful in
		250	practise.
		251
		252	=item ecb_cold
		253
		254	The opposite of C<ecb_hot> - declares a function as "cold" with regards to
		255	the cache, or in other words, this function is not called often, or not at
		256	speed-critical times, and keeping it in the cache might be a waste of said
		257	cache.
		258
		259	In addition to placing cold functions together (or at least away from hot
		260	functions), this knowledge can be used in other ways, for example, the
		261	function will be optimised for size, as opposed to speed, and codepaths
		262	leading to calls to those functions can automatically be marked as if
		263	C<ecb_expect_false> had been used to reach them.
		264
		265	Good examples for such functions would be error reporting functions, or
		266	functions only called in exceptional or rare cases.
		267
		268	=item ecb_artificial
		269
		270	Declares the function as "artificial", in this case meaning that this
		271	function is not really mean to be a function, but more like an accessor
		272	- many methods in C++ classes are mere accessor functions, and having a
		273	crash reported in such a method, or single-stepping through them, is not
		274	usually so helpful, especially when it's inlined to just a few instructions.
		275
		276	Marking them as artificial will instruct the debugger about just this,
		277	leading to happier debugging and thus happier lives.
		278
		279	Example: in some kind of smart-pointer class, mark the pointer accessor as
		280	artificial, so that the whole class acts more like a pointer and less like
		281	some C++ abstraction monster.
		282
		283	template<typename T>
		284	struct my_smart_ptr
		285	{
		286	T *value;
		287
		288	ecb_artificial
		289	operator T *()
		290	{
		291	return value;
		292	}
		293	};
		294
15	=back	295	=back
16		296
17	=head2 OPTIMISATION HINTS	297	=head2 OPTIMISATION HINTS
18		298
19	=over 4	299	=over 4
20		300
21	=item bool ecb_is_constant(expr)	301	=item bool ecb_is_constant(expr)
22		302
		303	Returns true iff the expression can be deduced to be a compile-time
		304	constant, and false otherwise.
		305
		306	For example, when you have a C<rndm16> function that returns a 16 bit
		307	random number, and you have a function that maps this to a range from
		308	0..n-1, then you could use this inline function in a header file:
		309
		310	ecb_inline uint32_t
		311	rndm (uint32_t n)
		312	{
		313	return (n * (uint32_t)rndm16 ()) >> 16;
		314	}
		315
		316	However, for powers of two, you could use a normal mask, but that is only
		317	worth it if, at compile time, you can detect this case. This is the case
		318	when the passed number is a constant and also a power of two (C<n & (n -
		319	1) == 0>):
		320
		321	ecb_inline uint32_t
		322	rndm (uint32_t n)
		323	{
		324	return is_constant (n) && !(n & (n - 1))
		325	? rndm16 () & (num - 1)
		326	: (n * (uint32_t)rndm16 ()) >> 16;
		327	}
		328
23	=item bool ecb_expect(expr,value)	329	=item bool ecb_expect (expr, value)
24		330
25	=item bool ecb_unlikely(bool)	331	Evaluates C<expr> and returns it. In addition, it tells the compiler that
		332	the C<expr> evaluates to C<value> a lot, which can be used for static
		333	branch optimisations.
26		334
27	=item bool ecb_likely(bool)	335	Usually, you want to use the more intuitive C<ecb_expect_true> and
		336	C<ecb_expect_false> functions instead.
28		337
		338	=item bool ecb_expect_true (cond)
		339
		340	=item bool ecb_expect_false (cond)
		341
		342	These two functions expect a expression that is true or false and return
		343	C<1> or C<0>, respectively, so when used in the condition of an C<if> or
		344	other conditional statement, it will not change the program:
		345
		346	/* these two do the same thing */
		347	if (some_condition) ...;
		348	if (ecb_expect_true (some_condition)) ...;
		349
		350	However, by using C<ecb_expect_true>, you tell the compiler that the
		351	condition is likely to be true (and for C<ecb_expect_false>, that it is
		352	unlikely to be true).
		353
		354	For example, when you check for a null pointer and expect this to be a
		355	rare, exceptional, case, then use C<ecb_expect_false>:
		356
		357	void my_free (void *ptr)
		358	{
		359	if (ecb_expect_false (ptr == 0))
		360	return;
		361	}
		362
		363	Consequent use of these functions to mark away exceptional cases or to
		364	tell the compiler what the hot path through a function is can increase
		365	performance considerably.
		366
		367	You might know these functions under the name C<likely> and C<unlikely>
		368	- while these are common aliases, we find that the expect name is easier
		369	to understand when quickly skimming code. If you wish, you can use
		370	C<ecb_likely> instead of C<ecb_expect_true> and C<ecb_unlikely> instead of
		371	C<ecb_expect_false> - these are simply aliases.
		372
		373	A very good example is in a function that reserves more space for some
		374	memory block (for example, inside an implementation of a string stream) -
		375	each time something is added, you have to check for a buffer overrun, but
		376	you expect that most checks will turn out to be false:
		377
		378	/* make sure we have "size" extra room in our buffer */
		379	ecb_inline void
		380	reserve (int size)
		381	{
		382	if (ecb_expect_false (current + size > end))
		383	real_reserve_method (size); /* presumably noinline */
		384	}
		385
29	=item bool ecb_assume(cond)	386	=item bool ecb_assume (cond)
30		387
		388	Try to tell the compiler that some condition is true, even if it's not
		389	obvious.
		390
		391	This can be used to teach the compiler about invariants or other
		392	conditions that might improve code generation, but which are impossible to
		393	deduce form the code itself.
		394
		395	For example, the example reservation function from the C<ecb_expect_false>
		396	description could be written thus (only C<ecb_assume> was added):
		397
		398	ecb_inline void
		399	reserve (int size)
		400	{
		401	if (ecb_expect_false (current + size > end))
		402	real_reserve_method (size); /* presumably noinline */
		403
		404	ecb_assume (current + size <= end);
		405	}
		406
		407	If you then call this function twice, like this:
		408
		409	reserve (10);
		410	reserve (1);
		411
		412	Then the compiler I<might> be able to optimise out the second call
		413	completely, as it knows that C<< current + 1 > end >> is false and the
		414	call will never be executed.
		415
31	=item bool ecb_unreachable()	416	=item bool ecb_unreachable ()
32		417
		418	This function does nothing itself, except tell the compiler that it will
		419	never be executed. Apart from suppressing a warning in some cases, this
		420	function can be used to implement C<ecb_assume> or similar functions.
		421
33	=item bool ecb_prefetch(addr,rw,locality)	422	=item bool ecb_prefetch (addr, rw, locality)
34		423
		424	Tells the compiler to try to prefetch memory at the given C<addr>ess
		425	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of
		426	C<0> means that there will only be one access later, C<3> means that
		427	the data will likely be accessed very often, and values in between mean
		428	something... in between. The memory pointed to by the address does not
		429	need to be accessible (it could be a null pointer for example), but C<rw>
		430	and C<locality> must be compile-time constants.
		431
		432	An obvious way to use this is to prefetch some data far away, in a big
		433	array you loop over. This prefetches memory some 128 array elements later,
		434	in the hope that it will be ready when the CPU arrives at that location.
		435
		436	int sum = 0;
		437
		438	for (i = 0; i < N; ++i)
		439	{
		440	sum += arr [i]
		441	ecb_prefetch (arr + i + 128, 0, 0);
		442	}
		443
		444	It's hard to predict how far to prefetch, and most CPUs that can prefetch
		445	are often good enough to predict this kind of behaviour themselves. It
		446	gets more interesting with linked lists, especially when you do some fair
		447	processing on each list element:
		448
		449	for (node *n = start; n; n = n->next)
		450	{
		451	ecb_prefetch (n->next, 0, 0);
		452	... do medium amount of work with *n
		453	}
		454
		455	After processing the node, (part of) the next node might already be in
		456	cache.
		457
35	=back	458	=back
36		459
37	=head2 BIT FIDDLING / BITSTUFFS	460	=head2 BIT FIDDLING / BIT WIZARDRY
38		461
		462	=over 4
		463
39	bool ecb_big_endian ();	464	=item bool ecb_big_endian ()
		465
40	bool ecb_little_endian ();	466	=item bool ecb_little_endian ()
		467
		468	These two functions return true if the byte order is big endian
		469	(most-significant byte first) or little endian (least-significant byte
		470	first) respectively.
		471
		472	On systems that are neither, their return values are unspecified.
		473
41	int ecb_ctz32 (uint32_t x);	474	=item int ecb_ctz32 (uint32_t x)
		475
		476	=item int ecb_ctz64 (uint64_t x)
		477
		478	Returns the index of the least significant bit set in C<x> (or
		479	equivalently the number of bits set to 0 before the least significant bit
		480	set), starting from 0. If C<x> is 0 the result is undefined.
		481
		482	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
		483
		484	For example:
		485
		486	ecb_ctz32 (3) = 0
		487	ecb_ctz32 (6) = 1
		488
		489	=item bool ecb_is_pot32 (uint32_t x)
		490
		491	=item bool ecb_is_pot64 (uint32_t x)
		492
		493	Return true iff C<x> is a power of two or C<x == 0>.
		494
		495	For smaller types then C<uint32_t> you can safely use C<ecb_is_pot32>.
		496
		497	=item int ecb_ld32 (uint32_t x)
		498
		499	=item int ecb_ld64 (uint64_t x)
		500
		501	Returns the index of the most significant bit set in C<x>, or the number
		502	of digits the number requires in binary (so that C<< 2**ld <= x <
		503	2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
		504	to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
		505	example to see how many bits a certain number requires to be encoded.
		506
		507	This function is similar to the "count leading zero bits" function, except
		508	that that one returns how many zero bits are "in front" of the number (in
		509	the given data type), while C<ecb_ld> returns how many bits the number
		510	itself requires.
		511
		512	For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
		513
42	int ecb_popcount32 (uint32_t x);	514	=item int ecb_popcount32 (uint32_t x)
		515
		516	=item int ecb_popcount64 (uint64_t x)
		517
		518	Returns the number of bits set to 1 in C<x>.
		519
		520	For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
		521
		522	For example:
		523
		524	ecb_popcount32 (7) = 3
		525	ecb_popcount32 (255) = 8
		526
		527	=item uint8_t ecb_bitrev8 (uint8_t x)
		528
		529	=item uint16_t ecb_bitrev16 (uint16_t x)
		530
43	uint32_t ecb_bswap32 (uint32_t x);	531	=item uint32_t ecb_bitrev32 (uint32_t x)
		532
		533	Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
		534	and so on.
		535
		536	Example:
		537
		538	ecb_bitrev8 (0xa7) = 0xea
		539	ecb_bitrev32 (0xffcc4411) = 0x882233ff
		540
44	uint32_t ecb_bswap16 (uint32_t x);	541	=item uint32_t ecb_bswap16 (uint32_t x)
		542
		543	=item uint32_t ecb_bswap32 (uint32_t x)
		544
		545	=item uint64_t ecb_bswap64 (uint64_t x)
		546
		547	These functions return the value of the 16-bit (32-bit, 64-bit) value
		548	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
		549	C<ecb_bswap32>).
		550
45	uint32_t ecb_rotr32 (uint32_t x, unsigned int count);	551	=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
		552
		553	=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
		554
46	uint32_t ecb_rotl32 (uint32_t x, unsigned int count);	555	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)
		556
		557	=item uint64_t ecb_rotl64 (uint64_t x, unsigned int count)
		558
		559	=item uint8_t ecb_rotr8 (uint8_t x, unsigned int count)
		560
		561	=item uint16_t ecb_rotr16 (uint16_t x, unsigned int count)
		562
		563	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)
		564
		565	=item uint64_t ecb_rotr64 (uint64_t x, unsigned int count)
		566
		567	These two families of functions return the value of C<x> after rotating
		568	all the bits by C<count> positions to the right (C<ecb_rotr>) or left
		569	(C<ecb_rotl>).
		570
		571	Current GCC versions understand these functions and usually compile them
		572	to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
		573	x86).
		574
		575	=back
47		576
48	=head2 ARITHMETIC	577	=head2 ARITHMETIC
49		578
		579	=over 4
		580
50	x = ecb_mod (m, n)	581	=item x = ecb_mod (m, n)
		582
		583	Returns C<m> modulo C<n>, which is the same as the positive remainder
		584	of the division operation between C<m> and C<n>, using floored
		585	division. Unlike the C remainder operator C<%>, this function ensures that
		586	the return value is always positive and that the two numbers I<m> and
		587	I<m' = m + i * n> result in the same value modulo I<n> - in other words,
		588	C<ecb_mod> implements the mathematical modulo operation, which is missing
		589	in the language.
		590
		591	C<n> must be strictly positive (i.e. C<< >= 1 >>), while C<m> must be
		592	negatable, that is, both C<m> and C<-m> must be representable in its
		593	type (this typically excludes the minimum signed integer value, the same
		594	limitation as for C</> and C<%> in C).
		595
		596	Current GCC versions compile this into an efficient branchless sequence on
		597	almost all CPUs.
		598
		599	For example, when you want to rotate forward through the members of an
		600	array for increasing C<m> (which might be negative), then you should use
		601	C<ecb_mod>, as the C<%> operator might give either negative results, or
		602	change direction for negative values:
		603
		604	for (m = -100; m <= 100; ++m)
		605	int elem = myarray [ecb_mod (m, ecb_array_length (myarray))];
		606
		607	=item x = ecb_div_rd (val, div)
		608
		609	=item x = ecb_div_ru (val, div)
		610
		611	Returns C<val> divided by C<div> rounded down or up, respectively.
		612	C<val> and C<div> must have integer types and C<div> must be strictly
		613	positive. Note that these functions are implemented with macros in C
		614	and with function templates in C++.
		615
		616	=back
51		617
52	=head2 UTILITY	618	=head2 UTILITY
53		619
54	ecb_array_length (name)	620	=over 4
55		621
		622	=item element_count = ecb_array_length (name)
56		623
		624	Returns the number of elements in the array C<name>. For example:
		625
		626	int primes[] = { 2, 3, 5, 7, 11 };
		627	int sum = 0;
		628
		629	for (i = 0; i < ecb_array_length (primes); i++)
		630	sum += primes [i];
		631
		632	=back
		633
		634	=head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF
		635
		636	These symbols need to be defined before including F<ecb.h> the first time.
		637
		638	=over 4
		639
		640	=item ECB_NO_THRADS
		641
		642	If F<ecb.h> is never used from multiple threads, then this symbol can
		643	be defined, in which case memory fences (and similar constructs) are
		644	completely removed, leading to more efficient code and fewer dependencies.
		645
		646	Setting this symbol to a true value implies C<ECB_NO_SMP>.
		647
		648	=item ECB_NO_SMP
		649
		650	The weaker version of C<ECB_NO_THREADS> - if F<ecb.h> is used from
		651	multiple threads, but never concurrently (e.g. if the system the program
		652	runs on has only a single CPU with a single core, no hyperthreading and so
		653	on), then this symbol can be defined, leading to more efficient code and
		654	fewer dependencies.
		655
		656	=back
		657
		658

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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 1.48 by root, Wed May 30 16:56:06 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 1.48 by root, Wed May 30 16:56:06 2012 UTC