[ViewVC] Diff of: cvs/libecb/ecb.pod

Comparing libecb/ecb.pod (file contents):
Revision 1.32 by sf-exg, Fri Jun 17 15:55:41 2011 UTC vs.
Revision 1.65 by root, Thu Feb 19 15:45:29 2015 UTC

…		…
54	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
55	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
56	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
57	refers to any kind of boolean value, not a specific type.	57	refers to any kind of boolean value, not a specific type.
58		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
		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	For C<ptrdiff_t> and C<size_t> use C<stddef.h>.
		72
		73	=head2 LANGUAGE/ENVIRONMENT/COMPILER VERSIONS
		74
		75	All the following symbols expand to an expression that can be tested in
		76	preprocessor instructions as well as treated as a boolean (use C<!!> to
		77	ensure it's either C<0> or C<1> if you need that).
		78
		79	=over 4
		80
		81	=item ECB_C
		82
		83	True if the implementation defines the C<__STDC__> macro to a true value,
		84	while not claiming to be C++.
		85
		86	=item ECB_C99
		87
		88	True if the implementation claims to be compliant to C99 (ISO/IEC
		89	9899:1999) or any later version, while not claiming to be C++.
		90
		91	Note that later versions (ECB_C11) remove core features again (for
		92	example, variable length arrays).
		93
		94	=item ECB_C11
		95
		96	True if the implementation claims to be compliant to C11 (ISO/IEC
		97	9899:2011) or any later version, while not claiming to be C++.
		98
		99	=item ECB_CPP
		100
		101	True if the implementation defines the C<__cplusplus__> macro to a true
		102	value, which is typically true for C++ compilers.
		103
		104	=item ECB_CPP11
		105
		106	True if the implementation claims to be compliant to ISO/IEC 14882:2011
		107	(C++11) or any later version.
		108
		109	=item ECB_GCC_VERSION (major, minor)
		110
		111	Expands to a true value (suitable for testing in by the preprocessor)
		112	if the compiler used is GNU C and the version is the given version, or
		113	higher.
		114
		115	This macro tries to return false on compilers that claim to be GCC
		116	compatible but aren't.
		117
		118	=item ECB_EXTERN_C
		119
		120	Expands to C<extern "C"> in C++, and a simple C<extern> in C.
		121
		122	This can be used to declare a single external C function:
		123
		124	ECB_EXTERN_C int printf (const char *format, ...);
		125
		126	=item ECB_EXTERN_C_BEG / ECB_EXTERN_C_END
		127
		128	These two macros can be used to wrap multiple C<extern "C"> definitions -
		129	they expand to nothing in C.
		130
		131	They are most useful in header files:
		132
		133	ECB_EXTERN_C_BEG
		134
		135	int mycfun1 (int x);
		136	int mycfun2 (int x);
		137
		138	ECB_EXTERN_C_END
		139
		140	=item ECB_STDFP
		141
		142	If this evaluates to a true value (suitable for testing in by the
		143	preprocessor), then C<float> and C<double> use IEEE 754 single/binary32
		144	and double/binary64 representations internally I<and> the endianness of
		145	both types match the endianness of C<uint32_t> and C<uint64_t>.
		146
		147	This means you can just copy the bits of a C<float> (or C<double>) to an
		148	C<uint32_t> (or C<uint64_t>) and get the raw IEEE 754 bit representation
		149	without having to think about format or endianness.
		150
		151	This is true for basically all modern platforms, although F<ecb.h> might
		152	not be able to deduce this correctly everywhere and might err on the safe
		153	side.
		154
		155	=item ECB_AMD64, ECB_AMD64_X32
		156
		157	These two macros are defined to C<1> on the x86_64/amd64 ABI and the X32
		158	ABI, respectively, and undefined elsewhere.
		159
		160	The designers of the new X32 ABI for some inexplicable reason decided to
		161	make it look exactly like amd64, even though it's completely incompatible
		162	to that ABI, breaking about every piece of software that assumed that
		163	C<__x86_64> stands for, well, the x86-64 ABI, making these macros
		164	necessary.
		165
		166	=back
		167
		168	=head2 MACRO TRICKERY
		169
		170	=over 4
		171
		172	=item ECB_CONCAT (a, b)
		173
		174	Expands any macros in C<a> and C<b>, then concatenates the result to form
		175	a single token. This is mainly useful to form identifiers from components,
		176	e.g.:
		177
		178	#define S1 str
		179	#define S2 cpy
		180
		181	ECB_CONCAT (S1, S2)(dst, src); // == strcpy (dst, src);
		182
		183	=item ECB_STRINGIFY (arg)
		184
		185	Expands any macros in C<arg> and returns the stringified version of
		186	it. This is mainly useful to get the contents of a macro in string form,
		187	e.g.:
		188
		189	#define SQL_LIMIT 100
		190	sql_exec ("select * from table limit " ECB_STRINGIFY (SQL_LIMIT));
		191
		192	=item ECB_STRINGIFY_EXPR (expr)
		193
		194	Like C<ECB_STRINGIFY>, but additionally evaluates C<expr> to make sure it
		195	is a valid expression. This is useful to catch typos or cases where the
		196	macro isn't available:
		197
		198	#include <errno.h>
		199
		200	ECB_STRINGIFY (EDOM); // "33" (on my system at least)
		201	ECB_STRINGIFY_EXPR (EDOM); // "33"
		202
		203	// now imagine we had a typo:
		204
		205	ECB_STRINGIFY (EDAM); // "EDAM"
		206	ECB_STRINGIFY_EXPR (EDAM); // error: EDAM undefined
		207
		208	=back
		209
59	=head2 GCC ATTRIBUTES	210	=head2 ATTRIBUTES
60		211
61	A major part of libecb deals with GCC attributes. These are additional	212	A major part of libecb deals with additional attributes that can be
62	attributes that you can assign to functions, variables and sometimes even	213	assigned to functions, variables and sometimes even types - much like
63	types - much like C<const> or C<volatile> in C.	214	C<const> or C<volatile> in C. They are implemented using either GCC
64		215	attributes or other compiler/language specific features. Attributes
65	While GCC allows declarations to show up in many surprising places,
66	but not in many expected places, the safest way is to put attribute
67	declarations before the whole declaration:	216	declarations must be put before the whole declaration:
68		217
69	ecb_const int mysqrt (int a);	218	ecb_const int mysqrt (int a);
70	ecb_unused int i;	219	ecb_unused int i;
71		220
72	For variables, it is often nicer to put the attribute after the name, and
73	avoid multiple declarations using commas:
74
75	int i ecb_unused;
76
77	=over 4	221	=over 4
78
79	=item ecb_attribute ((attrs...))
80
81	A simple wrapper that expands to C<__attribute__((attrs))> on GCC, and to
82	nothing on other compilers, so the effect is that only GCC sees these.
83
84	Example: use the C<deprecated> attribute on a function.
85
86	ecb_attribute((__deprecated__)) void
87	do_not_use_me_anymore (void);
88		222
89	=item ecb_unused	223	=item ecb_unused
90		224
91	Marks a function or a variable as "unused", which simply suppresses a	225	Marks a function or a variable as "unused", which simply suppresses a
92	warning by GCC when it detects it as unused. This is useful when you e.g.	226	warning by GCC when it detects it as unused. This is useful when you e.g.
93	declare a variable but do not always use it:	227	declare a variable but do not always use it:
94		228
95	{	229	{
96	int var ecb_unused;	230	ecb_unused int var;
97		231
98	#ifdef SOMECONDITION	232	#ifdef SOMECONDITION
99	var = ...;	233	var = ...;
100	return var;	234	return var;
101	#else	235	#else
102	return 0;	236	return 0;
103	#endif	237	#endif
104	}	238	}
105		239
		240	=item ecb_deprecated
		241
		242	Similar to C<ecb_unused>, but marks a function, variable or type as
		243	deprecated. This makes some compilers warn when the type is used.
		244
		245	=item ecb_deprecated_message (message)
		246
		247	Same as C<ecb_deprecated>, but if possible, supply a diagnostic that is
		248	used instead of a generic depreciation message when the object is being
		249	used.
		250
106	=item ecb_inline	251	=item ecb_inline
107		252
108	This is not actually an attribute, but you use it like one. It expands
109	either to C<static inline> or to just C<static>, if inline isn't	253	Expands either to C<static inline> or to just C<static>, if inline
110	supported. It should be used to declare functions that should be inlined,	254	isn't supported. It should be used to declare functions that should be
111	for code size or speed reasons.	255	inlined, for code size or speed reasons.
112		256
113	Example: inline this function, it surely will reduce codesize.	257	Example: inline this function, it surely will reduce codesize.
114		258
115	ecb_inline int	259	ecb_inline int
116	negmul (int a, int b)	260	negmul (int a, int b)
…		…
138	}	282	}
139		283
140	In this case, the compiler would probably be smart enough to deduce it on	284	In this case, the compiler would probably be smart enough to deduce it on
141	its own, so this is mainly useful for declarations.	285	its own, so this is mainly useful for declarations.
142		286
		287	=item ecb_restrict
		288
		289	Expands to the C<restrict> keyword or equivalent on compilers that support
		290	them, and to nothing on others. Must be specified on a pointer type or
		291	an array index to indicate that the memory doesn't alias with any other
		292	restricted pointer in the same scope.
		293
		294	Example: multiply a vector, and allow the compiler to parallelise the
		295	loop, because it knows it doesn't overwrite input values.
		296
		297	void
		298	multiply (ecb_restrict float *src,
		299	ecb_restrict float *dst,
		300	int len, float factor)
		301	{
		302	int i;
		303
		304	for (i = 0; i < len; ++i)
		305	dst [i] = src [i] * factor;
		306	}
		307
143	=item ecb_const	308	=item ecb_const
144		309
145	Declares that the function only depends on the values of its arguments,	310	Declares that the function only depends on the values of its arguments,
146	much like a mathematical function. It specifically does not read or write	311	much like a mathematical function. It specifically does not read or write
147	any memory any arguments might point to, global variables, or call any	312	any memory any arguments might point to, global variables, or call any
…		…
207	functions only called in exceptional or rare cases.	372	functions only called in exceptional or rare cases.
208		373
209	=item ecb_artificial	374	=item ecb_artificial
210		375
211	Declares the function as "artificial", in this case meaning that this	376	Declares the function as "artificial", in this case meaning that this
212	function is not really mean to be a function, but more like an accessor	377	function is not really meant to be a function, but more like an accessor
213	- many methods in C++ classes are mere accessor functions, and having a	378	- many methods in C++ classes are mere accessor functions, and having a
214	crash reported in such a method, or single-stepping through them, is not	379	crash reported in such a method, or single-stepping through them, is not
215	usually so helpful, especially when it's inlined to just a few instructions.	380	usually so helpful, especially when it's inlined to just a few instructions.
216		381
217	Marking them as artificial will instruct the debugger about just this,	382	Marking them as artificial will instruct the debugger about just this,
…		…
237		402
238	=head2 OPTIMISATION HINTS	403	=head2 OPTIMISATION HINTS
239		404
240	=over 4	405	=over 4
241		406
242	=item bool ecb_is_constant(expr)	407	=item bool ecb_is_constant (expr)
243		408
244	Returns true iff the expression can be deduced to be a compile-time	409	Returns true iff the expression can be deduced to be a compile-time
245	constant, and false otherwise.	410	constant, and false otherwise.
246		411
247	For example, when you have a C<rndm16> function that returns a 16 bit	412	For example, when you have a C<rndm16> function that returns a 16 bit
…		…
265	return is_constant (n) && !(n & (n - 1))	430	return is_constant (n) && !(n & (n - 1))
266	? rndm16 () & (num - 1)	431	? rndm16 () & (num - 1)
267	: (n * (uint32_t)rndm16 ()) >> 16;	432	: (n * (uint32_t)rndm16 ()) >> 16;
268	}	433	}
269		434
270	=item bool ecb_expect (expr, value)	435	=item ecb_expect (expr, value)
271		436
272	Evaluates C<expr> and returns it. In addition, it tells the compiler that	437	Evaluates C<expr> and returns it. In addition, it tells the compiler that
273	the C<expr> evaluates to C<value> a lot, which can be used for static	438	the C<expr> evaluates to C<value> a lot, which can be used for static
274	branch optimisations.	439	branch optimisations.
275		440
…		…
322	{	487	{
323	if (ecb_expect_false (current + size > end))	488	if (ecb_expect_false (current + size > end))
324	real_reserve_method (size); /* presumably noinline */	489	real_reserve_method (size); /* presumably noinline */
325	}	490	}
326		491
327	=item bool ecb_assume (cond)	492	=item ecb_assume (cond)
328		493
329	Try to tell the compiler that some condition is true, even if it's not	494	Try to tell the compiler that some condition is true, even if it's not
330	obvious.	495	obvious. This is not a function, but a statement: it cannot be used in
		496	another expression.
331		497
332	This can be used to teach the compiler about invariants or other	498	This can be used to teach the compiler about invariants or other
333	conditions that might improve code generation, but which are impossible to	499	conditions that might improve code generation, but which are impossible to
334	deduce form the code itself.	500	deduce form the code itself.
335		501
…		…
352		518
353	Then the compiler I<might> be able to optimise out the second call	519	Then the compiler I<might> be able to optimise out the second call
354	completely, as it knows that C<< current + 1 > end >> is false and the	520	completely, as it knows that C<< current + 1 > end >> is false and the
355	call will never be executed.	521	call will never be executed.
356		522
357	=item bool ecb_unreachable ()	523	=item ecb_unreachable ()
358		524
359	This function does nothing itself, except tell the compiler that it will	525	This function does nothing itself, except tell the compiler that it will
360	never be executed. Apart from suppressing a warning in some cases, this	526	never be executed. Apart from suppressing a warning in some cases, this
361	function can be used to implement C<ecb_assume> or similar functions.	527	function can be used to implement C<ecb_assume> or similar functionality.
362		528
363	=item bool ecb_prefetch (addr, rw, locality)	529	=item ecb_prefetch (addr, rw, locality)
364		530
365	Tells the compiler to try to prefetch memory at the given C<addr>ess	531	Tells the compiler to try to prefetch memory at the given C<addr>ess
366	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of	532	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of
367	C<0> means that there will only be one access later, C<3> means that	533	C<0> means that there will only be one access later, C<3> means that
368	the data will likely be accessed very often, and values in between mean	534	the data will likely be accessed very often, and values in between mean
369	something... in between. The memory pointed to by the address does not	535	something... in between. The memory pointed to by the address does not
370	need to be accessible (it could be a null pointer for example), but C<rw>	536	need to be accessible (it could be a null pointer for example), but C<rw>
371	and C<locality> must be compile-time constants.	537	and C<locality> must be compile-time constants.
372		538
		539	This is a statement, not a function: you cannot use it as part of an
		540	expression.
		541
373	An obvious way to use this is to prefetch some data far away, in a big	542	An obvious way to use this is to prefetch some data far away, in a big
374	array you loop over. This prefetches memory some 128 array elements later,	543	array you loop over. This prefetches memory some 128 array elements later,
375	in the hope that it will be ready when the CPU arrives at that location.	544	in the hope that it will be ready when the CPU arrives at that location.
376		545
377	int sum = 0;	546	int sum = 0;
…		…
396	After processing the node, (part of) the next node might already be in	565	After processing the node, (part of) the next node might already be in
397	cache.	566	cache.
398		567
399	=back	568	=back
400		569
401	=head2 BIT FIDDLING / BITSTUFFS	570	=head2 BIT FIDDLING / BIT WIZARDRY
402		571
403	=over 4	572	=over 4
404		573
405	=item bool ecb_big_endian ()	574	=item bool ecb_big_endian ()
406		575
…		…
412		581
413	On systems that are neither, their return values are unspecified.	582	On systems that are neither, their return values are unspecified.
414		583
415	=item int ecb_ctz32 (uint32_t x)	584	=item int ecb_ctz32 (uint32_t x)
416		585
		586	=item int ecb_ctz64 (uint64_t x)
		587
417	Returns the index of the least significant bit set in C<x> (or	588	Returns the index of the least significant bit set in C<x> (or
418	equivalently the number of bits set to 0 before the least significant bit	589	equivalently the number of bits set to 0 before the least significant bit
419	set), starting from 0. If C<x> is 0 the result is undefined. For example:	590	set), starting from 0. If C<x> is 0 the result is undefined.
		591
		592	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
		593
		594	For example:
420		595
421	ecb_ctz32 (3) = 0	596	ecb_ctz32 (3) = 0
422	ecb_ctz32 (6) = 1	597	ecb_ctz32 (6) = 1
423		598
		599	=item bool ecb_is_pot32 (uint32_t x)
		600
		601	=item bool ecb_is_pot64 (uint32_t x)
		602
		603	Return true iff C<x> is a power of two or C<x == 0>.
		604
		605	For smaller types then C<uint32_t> you can safely use C<ecb_is_pot32>.
		606
		607	=item int ecb_ld32 (uint32_t x)
		608
		609	=item int ecb_ld64 (uint64_t x)
		610
		611	Returns the index of the most significant bit set in C<x>, or the number
		612	of digits the number requires in binary (so that C<< 2**ld <= x <
		613	2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
		614	to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
		615	example to see how many bits a certain number requires to be encoded.
		616
		617	This function is similar to the "count leading zero bits" function, except
		618	that that one returns how many zero bits are "in front" of the number (in
		619	the given data type), while C<ecb_ld> returns how many bits the number
		620	itself requires.
		621
		622	For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
		623
424	=item int ecb_popcount32 (uint32_t x)	624	=item int ecb_popcount32 (uint32_t x)
425		625
		626	=item int ecb_popcount64 (uint64_t x)
		627
426	Returns the number of bits set to 1 in C<x>. For example:	628	Returns the number of bits set to 1 in C<x>.
		629
		630	For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
		631
		632	For example:
427		633
428	ecb_popcount32 (7) = 3	634	ecb_popcount32 (7) = 3
429	ecb_popcount32 (255) = 8	635	ecb_popcount32 (255) = 8
430		636
		637	=item uint8_t ecb_bitrev8 (uint8_t x)
		638
		639	=item uint16_t ecb_bitrev16 (uint16_t x)
		640
		641	=item uint32_t ecb_bitrev32 (uint32_t x)
		642
		643	Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
		644	and so on.
		645
		646	Example:
		647
		648	ecb_bitrev8 (0xa7) = 0xea
		649	ecb_bitrev32 (0xffcc4411) = 0x882233ff
		650
431	=item uint32_t ecb_bswap16 (uint32_t x)	651	=item uint32_t ecb_bswap16 (uint32_t x)
432		652
433	=item uint32_t ecb_bswap32 (uint32_t x)	653	=item uint32_t ecb_bswap32 (uint32_t x)
434		654
		655	=item uint64_t ecb_bswap64 (uint64_t x)
		656
435	These two functions return the value of the 16-bit (32-bit) value C<x>	657	These functions return the value of the 16-bit (32-bit, 64-bit) value
436	after reversing the order of bytes (0x11223344 becomes 0x44332211).	658	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
		659	C<ecb_bswap32>).
		660
		661	=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
		662
		663	=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
		664
		665	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)
		666
		667	=item uint64_t ecb_rotl64 (uint64_t x, unsigned int count)
		668
		669	=item uint8_t ecb_rotr8 (uint8_t x, unsigned int count)
		670
		671	=item uint16_t ecb_rotr16 (uint16_t x, unsigned int count)
437		672
438	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)	673	=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)
439		674
440	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)	675	=item uint64_t ecb_rotr64 (uint64_t x, unsigned int count)
441		676
442	These two functions return the value of C<x> after rotating all the bits	677	These two families of functions return the value of C<x> after rotating
443	by C<count> positions to the right or left respectively.	678	all the bits by C<count> positions to the right (C<ecb_rotr>) or left
		679	(C<ecb_rotl>).
444		680
445	Current GCC versions understand these functions and usually compile them	681	Current GCC versions understand these functions and usually compile them
446	to "optimal" code (e.g. a single C<roll> on x86).	682	to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
		683	x86).
		684
		685	=back
		686
		687	=head2 FLOATING POINT FIDDLING
		688
		689	=over 4
		690
		691	=item ECB_INFINITY
		692
		693	Evaluates to positive infinity if supported by the platform, otherwise to
		694	a truly huge number.
		695
		696	=item ECB_NAN
		697
		698	Evaluates to a quiet NAN if supported by the platform, otherwise to
		699	C<ECB_INFINITY>.
		700
		701	=item float ecb_ldexpf (float x, int exp)
		702
		703	Same as C<ldexpf>, but always available.
		704
		705	=item uint32_t ecb_float_to_binary32 (float x) [-UECB_NO_LIBM]
		706
		707	=item uint64_t ecb_double_to_binary64 (double x) [-UECB_NO_LIBM]
		708
		709	These functions each take an argument in the native C<float> or C<double>
		710	type and return the IEEE 754 bit representation of it.
		711
		712	The bit representation is just as IEEE 754 defines it, i.e. the sign bit
		713	will be the most significant bit, followed by exponent and mantissa.
		714
		715	This function should work even when the native floating point format isn't
		716	IEEE compliant, of course at a speed and code size penalty, and of course
		717	also within reasonable limits (it tries to convert NaNs, infinities and
		718	denormals, but will likely convert negative zero to positive zero).
		719
		720	On all modern platforms (where C<ECB_STDFP> is true), the compiler should
		721	be able to optimise away this function completely.
		722
		723	These functions can be helpful when serialising floats to the network - you
		724	can serialise the return value like a normal uint32_t/uint64_t.
		725
		726	Another use for these functions is to manipulate floating point values
		727	directly.
		728
		729	Silly example: toggle the sign bit of a float.
		730
		731	/* On gcc-4.7 on amd64, */
		732	/* this results in a single add instruction to toggle the bit, and 4 extra */
		733	/* instructions to move the float value to an integer register and back. */
		734
		735	x = ecb_binary32_to_float (ecb_float_to_binary32 (x) ^ 0x80000000U)
		736
		737	=item float ecb_binary16_to_float (uint16_t x) [-UECB_NO_LIBM]
		738
		739	=item float ecb_binary32_to_float (uint32_t x) [-UECB_NO_LIBM]
		740
		741	=item double ecb_binary32_to_double (uint64_t x) [-UECB_NO_LIBM]
		742
		743	The reverse operation of the previous function - takes the bit
		744	representation of an IEEE binary16, binary32 or binary64 number and
		745	converts it to the native C<float> or C<double> format.
		746
		747	This function should work even when the native floating point format isn't
		748	IEEE compliant, of course at a speed and code size penalty, and of course
		749	also within reasonable limits (it tries to convert normals and denormals,
		750	and might be lucky for infinities, and with extraordinary luck, also for
		751	negative zero).
		752
		753	On all modern platforms (where C<ECB_STDFP> is true), the compiler should
		754	be able to optimise away this function completely.
447		755
448	=back	756	=back
449		757
450	=head2 ARITHMETIC	758	=head2 ARITHMETIC
451		759
…		…
475	change direction for negative values:	783	change direction for negative values:
476		784
477	for (m = -100; m <= 100; ++m)	785	for (m = -100; m <= 100; ++m)
478	int elem = myarray [ecb_mod (m, ecb_array_length (myarray))];	786	int elem = myarray [ecb_mod (m, ecb_array_length (myarray))];
479		787
		788	=item x = ecb_div_rd (val, div)
		789
		790	=item x = ecb_div_ru (val, div)
		791
		792	Returns C<val> divided by C<div> rounded down or up, respectively.
		793	C<val> and C<div> must have integer types and C<div> must be strictly
		794	positive. Note that these functions are implemented with macros in C
		795	and with function templates in C++.
		796
480	=back	797	=back
481		798
482	=head2 UTILITY	799	=head2 UTILITY
483		800
484	=over 4	801	=over 4
…		…
493	for (i = 0; i < ecb_array_length (primes); i++)	810	for (i = 0; i < ecb_array_length (primes); i++)
494	sum += primes [i];	811	sum += primes [i];
495		812
496	=back	813	=back
497		814
		815	=head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF
498		816
		817	These symbols need to be defined before including F<ecb.h> the first time.
		818
		819	=over 4
		820
		821	=item ECB_NO_THREADS
		822
		823	If F<ecb.h> is never used from multiple threads, then this symbol can
		824	be defined, in which case memory fences (and similar constructs) are
		825	completely removed, leading to more efficient code and fewer dependencies.
		826
		827	Setting this symbol to a true value implies C<ECB_NO_SMP>.
		828
		829	=item ECB_NO_SMP
		830
		831	The weaker version of C<ECB_NO_THREADS> - if F<ecb.h> is used from
		832	multiple threads, but never concurrently (e.g. if the system the program
		833	runs on has only a single CPU with a single core, no hyperthreading and so
		834	on), then this symbol can be defined, leading to more efficient code and
		835	fewer dependencies.
		836
		837	=item ECB_NO_LIBM
		838
		839	When defined to C<1>, do not export any functions that might introduce
		840	dependencies on the math library (usually called F<-lm>) - these are
		841	marked with [-UECB_NO_LIBM].
		842
		843	=back
		844
		845

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Comparing libecb/ecb.pod (file contents): Revision 1.32 by sf-exg, Fri Jun 17 15:55:41 2011 UTC vs. Revision 1.65 by root, Thu Feb 19 15:45:29 2015 UTC

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Comparing libecb/ecb.pod (file contents):
Revision 1.32 by sf-exg, Fri Jun 17 15:55:41 2011 UTC vs.
Revision 1.65 by root, Thu Feb 19 15:45:29 2015 UTC