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Revision 1.15 by root, Thu May 26 23:26:29 2011 UTC vs.
Revision 1.48 by root, Wed May 30 16:56:06 2012 UTC

…		…
3	=head2 ABOUT LIBECB	3	=head2 ABOUT LIBECB
4		4
5	Libecb is currently a simple header file that doesn't require any	5	Libecb is currently a simple header file that doesn't require any
6	configuration to use or include in your project.	6	configuration to use or include in your project.
7		7
8	It's part of the e-suite of libraries, other memembers of which include	8	It's part of the e-suite of libraries, other members of which include
9	libev and libeio.	9	libev and libeio.
10		10
11	Its homepage can be found here:	11	Its homepage can be found here:
12		12
13	http://software.schmorp.de/pkg/libecb	13	http://software.schmorp.de/pkg/libecb
14		14
15	It mainly provides a number of wrappers around GCC built-ins, together	15	It mainly provides a number of wrappers around GCC built-ins, together
16	with replacement functions for other compilers. In addition to this,	16	with replacement functions for other compilers. In addition to this,
17	it provides a number of other lowlevel C utilities, such endienness	17	it provides a number of other lowlevel C utilities, such as endianness
18	detection, byte swapping or bit rotations.	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.
19		23
20	More might come.	24	More might come.
21		25
22	=head2 ABOUT THE HEADER	26	=head2 ABOUT THE HEADER
23		27
…		…
27	#include <ecb.h>	31	#include <ecb.h>
28		32
29	The header should work fine for both C and C++ compilation, and gives you	33	The header should work fine for both C and C++ compilation, and gives you
30	all of F<inttypes.h> in addition to the ECB symbols.	34	all of F<inttypes.h> in addition to the ECB symbols.
31		35
32	There are currently no objetc files to link to - future versions might	36	There are currently no object files to link to - future versions might
33	come with an (optional) object code library to link against, to reduce	37	come with an (optional) object code library to link against, to reduce
34	code size or gain access to additional features.	38	code size or gain access to additional features.
35		39
36	It also currently includes everything from F<inttypes.h>.	40	It also currently includes everything from F<inttypes.h>.
37		41
…		…
50	only a generic name is used (C<expr>, C<cond>, C<value> and so on), then	54	only a generic name is used (C<expr>, C<cond>, C<value> and so on), then
51	the corresponding function relies on C to implement the correct types, and	55	the corresponding function relies on C to implement the correct types, and
52	is usually implemented as a macro. Specifically, a "bool" in this manual	56	is usually implemented as a macro. Specifically, a "bool" in this manual
53	refers to any kind of boolean value, not a specific type.	57	refers to any kind of boolean value, not a specific type.
54		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
		117
55	=head2 GCC ATTRIBUTES	118	=head2 GCC ATTRIBUTES
56		119
57	blabla where to put, what others	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;
58		135
59	=over 4	136	=over 4
60		137
61	=item ecb_attribute ((attrs...))	138	=item ecb_attribute ((attrs...))
62		139
…		…
83	#else	160	#else
84	return 0;	161	return 0;
85	#endif	162	#endif
86	}	163	}
87		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
88	=item ecb_noinline	180	=item ecb_noinline
89		181
90	Prevent a function from being inlined - it might be optimised away, but	182	Prevent a function from being inlined - it might be optimised away, but
91	not inlined into other functions. This is useful if you know your function	183	not inlined into other functions. This is useful if you know your function
92	is rarely called and large enough for inlining not to be helpful.	184	is rarely called and large enough for inlining not to be helpful.
93		185
94	=item ecb_noreturn	186	=item ecb_noreturn
95		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
96	=item ecb_const	202	=item ecb_const
97		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
98	=item ecb_pure	223	=item ecb_pure
99		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
100	=item ecb_hot	239	=item ecb_hot
101		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
102	=item ecb_cold	252	=item ecb_cold
103		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
104	=item ecb_artificial	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	};
105		294
106	=back	295	=back
107		296
108	=head2 OPTIMISATION HINTS	297	=head2 OPTIMISATION HINTS
109		298
…		…
141		330
142	Evaluates C<expr> and returns it. In addition, it tells the compiler that	331	Evaluates C<expr> and returns it. In addition, it tells the compiler that
143	the C<expr> evaluates to C<value> a lot, which can be used for static	332	the C<expr> evaluates to C<value> a lot, which can be used for static
144	branch optimisations.	333	branch optimisations.
145		334
146	Usually, you want to use the more intuitive C<ecb_likely> and	335	Usually, you want to use the more intuitive C<ecb_expect_true> and
147	C<ecb_unlikely> functions instead.	336	C<ecb_expect_false> functions instead.
148		337
		338	=item bool ecb_expect_true (cond)
		339
149	=item bool ecb_likely (cond)	340	=item bool ecb_expect_false (cond)
150
151	=item bool ecb_unlikely (cond)
152		341
153	These two functions expect a expression that is true or false and return	342	These two functions expect a expression that is true or false and return
154	C<1> or C<0>, respectively, so when used in the condition of an C<if> or	343	C<1> or C<0>, respectively, so when used in the condition of an C<if> or
155	other conditional statement, it will not change the program:	344	other conditional statement, it will not change the program:
156		345
157	/* these two do the same thing */	346	/* these two do the same thing */
158	if (some_condition) ...;	347	if (some_condition) ...;
159	if (ecb_likely (some_condition)) ...;	348	if (ecb_expect_true (some_condition)) ...;
160		349
161	However, by using C<ecb_likely>, you tell the compiler that the condition	350	However, by using C<ecb_expect_true>, you tell the compiler that the
162	is likely to be true (and for C<ecb_unlikely>, that it is unlikely to be	351	condition is likely to be true (and for C<ecb_expect_false>, that it is
163	true).	352	unlikely to be true).
164		353
165	For example, when you check for a null pointer and expect this to be a	354	For example, when you check for a null pointer and expect this to be a
166	rare, exceptional, case, then use C<ecb_unlikely>:	355	rare, exceptional, case, then use C<ecb_expect_false>:
167		356
168	void my_free (void *ptr)	357	void my_free (void *ptr)
169	{	358	{
170	if (ecb_unlikely (ptr == 0))	359	if (ecb_expect_false (ptr == 0))
171	return;	360	return;
172	}	361	}
173		362
174	Consequent use of these functions to mark away exceptional cases or to	363	Consequent use of these functions to mark away exceptional cases or to
175	tell the compiler what the hot path through a function is can increase	364	tell the compiler what the hot path through a function is can increase
176	performance considerably.	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.
177		372
178	A very good example is in a function that reserves more space for some	373	A very good example is in a function that reserves more space for some
179	memory block (for example, inside an implementation of a string stream) -	374	memory block (for example, inside an implementation of a string stream) -
180	each time something is added, you have to check for a buffer overrun, but	375	each time something is added, you have to check for a buffer overrun, but
181	you expect that most checks will turn out to be false:	376	you expect that most checks will turn out to be false:
182		377
183	/* make sure we have "size" extra room in our buffer */	378	/* make sure we have "size" extra room in our buffer */
184	ecb_inline void	379	ecb_inline void
185	reserve (int size)	380	reserve (int size)
186	{	381	{
187	if (ecb_unlikely (current + size > end))	382	if (ecb_expect_false (current + size > end))
188	real_reserve_method (size); /* presumably noinline */	383	real_reserve_method (size); /* presumably noinline */
189	}	384	}
190		385
191	=item bool ecb_assume (cond)	386	=item bool ecb_assume (cond)
192		387
…		…
195		390
196	This can be used to teach the compiler about invariants or other	391	This can be used to teach the compiler about invariants or other
197	conditions that might improve code generation, but which are impossible to	392	conditions that might improve code generation, but which are impossible to
198	deduce form the code itself.	393	deduce form the code itself.
199		394
200	For example, the example reservation function from the C<ecb_unlikely>	395	For example, the example reservation function from the C<ecb_expect_false>
201	description could be written thus (only C<ecb_assume> was added):	396	description could be written thus (only C<ecb_assume> was added):
202		397
203	ecb_inline void	398	ecb_inline void
204	reserve (int size)	399	reserve (int size)
205	{	400	{
206	if (ecb_unlikely (current + size > end))	401	if (ecb_expect_false (current + size > end))
207	real_reserve_method (size); /* presumably noinline */	402	real_reserve_method (size); /* presumably noinline */
208		403
209	ecb_assume (current + size <= end);	404	ecb_assume (current + size <= end);
210	}	405	}
211		406
…		…
260	After processing the node, (part of) the next node might already be in	455	After processing the node, (part of) the next node might already be in
261	cache.	456	cache.
262		457
263	=back	458	=back
264		459
265	=head2 BIT FIDDLING / BITSTUFFS	460	=head2 BIT FIDDLING / BIT WIZARDRY
266		461
267	=over 4	462	=over 4
268		463
269	=item bool ecb_big_endian ()	464	=item bool ecb_big_endian ()
270		465
…		…
272		467
273	These two functions return true if the byte order is big endian	468	These two functions return true if the byte order is big endian
274	(most-significant byte first) or little endian (least-significant byte	469	(most-significant byte first) or little endian (least-significant byte
275	first) respectively.	470	first) respectively.
276		471
		472	On systems that are neither, their return values are unspecified.
		473
277	=item int ecb_ctz32 (uint32_t x)	474	=item int ecb_ctz32 (uint32_t x)
278		475
		476	=item int ecb_ctz64 (uint64_t x)
		477
279	Returns the index of the least significant bit set in C<x> (or	478	Returns the index of the least significant bit set in C<x> (or
280	equivalently the number of bits set to 0 before the least significant	479	equivalently the number of bits set to 0 before the least significant bit
281	bit set), starting from 0. If C<x> is 0 the result is undefined. A	480	set), starting from 0. If C<x> is 0 the result is undefined.
282	common use case is to compute the integer binary logarithm, i.e.,	481
283	floor(log2(n)). For example:	482	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
		483
		484	For example:
284		485
285	ecb_ctz32 (3) = 0	486	ecb_ctz32 (3) = 0
286	ecb_ctz32 (6) = 1	487	ecb_ctz32 (6) = 1
287		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
288	=item int ecb_popcount32 (uint32_t x)	514	=item int ecb_popcount32 (uint32_t x)
289		515
		516	=item int ecb_popcount64 (uint64_t x)
		517
290	Returns the number of bits set to 1 in C<x>. For example:	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:
291		523
292	ecb_popcount32 (7) = 3	524	ecb_popcount32 (7) = 3
293	ecb_popcount32 (255) = 8	525	ecb_popcount32 (255) = 8
294		526
		527	=item uint8_t ecb_bitrev8 (uint8_t x)
		528
		529	=item uint16_t ecb_bitrev16 (uint16_t x)
		530
		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
295	=item uint32_t ecb_bswap16 (uint32_t x)	541	=item uint32_t ecb_bswap16 (uint32_t x)
296		542
297	=item uint32_t ecb_bswap32 (uint32_t x)	543	=item uint32_t ecb_bswap32 (uint32_t x)
298		544
		545	=item uint64_t ecb_bswap64 (uint64_t x)
		546
299	These two functions return the value of the 16-bit (32-bit) variable	547	These functions return the value of the 16-bit (32-bit, 64-bit) value
300	C<x> after reversing the order of bytes.	548	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
		549	C<ecb_bswap32>).
		550
		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
		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)
301		562
302	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)	563	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)
303		564
304	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)	565	=item uint64_t ecb_rotr64 (uint64_t x, unsigned int count)
305		566
306	These two functions return the value of C<x> after shifting all the bits	567	These two families of functions return the value of C<x> after rotating
307	by C<count> positions to the right or left respectively.	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).
308		574
309	=back	575	=back
310		576
311	=head2 ARITHMETIC	577	=head2 ARITHMETIC
312		578
313	=over 4	579	=over 4
314		580
315	=item x = ecb_mod (m, n)	581	=item x = ecb_mod (m, n)
316		582
317	Returns the positive remainder of the modulo operation between C<m> and	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
318	C<n>. Unlike the C moduloe operator C<%>, this function ensures that the	585	division. Unlike the C remainder operator C<%>, this function ensures that
319	return value is always positive).	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.
320		590
321	C<n> must be strictly positive (i.e. C<< >1 >>), while C<m> must be	591	C<n> must be strictly positive (i.e. C<< >= 1 >>), while C<m> must be
322	negatable, that is, both C<m> and C<-m> must be representable in its	592	negatable, that is, both C<m> and C<-m> must be representable in its
323	type.	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++.
324		615
325	=back	616	=back
326		617
327	=head2 UTILITY	618	=head2 UTILITY
328		619
329	=over 4	620	=over 4
330		621
331	=item element_count = ecb_array_length (name) [MACRO]	622	=item element_count = ecb_array_length (name)
332		623
333	Returns the number of elements in the array C<name>. For example:	624	Returns the number of elements in the array C<name>. For example:
334		625
335	int primes[] = { 2, 3, 5, 7, 11 };	626	int primes[] = { 2, 3, 5, 7, 11 };
336	int sum = 0;	627	int sum = 0;
…		…
338	for (i = 0; i < ecb_array_length (primes); i++)	629	for (i = 0; i < ecb_array_length (primes); i++)
339	sum += primes [i];	630	sum += primes [i];
340		631
341	=back	632	=back
342		633
		634	=head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF
343		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 cvsroot/libecb/ecb.pod (file contents): Revision 1.15 by root, Thu May 26 23:26:29 2011 UTC vs. Revision 1.48 by root, Wed May 30 16:56:06 2012 UTC

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Comparing cvsroot/libecb/ecb.pod (file contents):
Revision 1.15 by root, Thu May 26 23:26:29 2011 UTC vs.
Revision 1.48 by root, Wed May 30 16:56:06 2012 UTC