| … | |
… | |
| 53 | C<uint32_t>, then the corresponding function works only with that type. If |
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 |
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. |
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58 | |
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59 | =head2 TYPES / TYPE SUPPORT |
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60 | |
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61 | ecb.h makes sure that the following types are defined (in the expected way): |
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62 | |
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63 | int8_t uint8_t int16_t uint16_t |
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64 | int32_t uint32_t int64_t uint64_t |
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65 | intptr_t uintptr_t ptrdiff_t |
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66 | |
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67 | The macro C<ECB_PTRSIZE> is defined to the size of a pointer on this |
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68 | platform (currently C<4> or C<8>). |
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69 | |
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70 | =head2 LANGUAGE/COMPILER VERSIONS |
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71 | |
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72 | =over 4 |
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73 | |
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74 | =item ECB_C99 |
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75 | |
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76 | Expands to a true value (suitable for testing in by the preprocessor) |
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77 | if the environment claims to be C99 compliant. |
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78 | |
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79 | =item ECB_C11 |
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80 | |
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81 | Expands to a true value (suitable for testing in by the preprocessor) |
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82 | if the environment claims to be C11 compliant. |
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83 | |
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84 | =item ECB_GCC_VERSION(major,minor) |
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85 | |
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86 | Expands to a true value (suitable for testing in by the preprocessor) |
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87 | if the compiler used is GNU C and the version is the givne version, or |
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88 | higher. |
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89 | |
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90 | This macro tries to return false on compilers that claim to be GCC |
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91 | compatible but aren't. |
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92 | |
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93 | =back |
| 58 | |
94 | |
| 59 | =head2 GCC ATTRIBUTES |
95 | =head2 GCC ATTRIBUTES |
| 60 | |
96 | |
| 61 | A major part of libecb deals with GCC attributes. These are additional |
97 | A major part of libecb deals with GCC attributes. These are additional |
| 62 | attributes that you can assign to functions, variables and sometimes even |
98 | attributes that you can assign to functions, variables and sometimes even |
| … | |
… | |
| 425 | For example: |
461 | For example: |
| 426 | |
462 | |
| 427 | ecb_ctz32 (3) = 0 |
463 | ecb_ctz32 (3) = 0 |
| 428 | ecb_ctz32 (6) = 1 |
464 | ecb_ctz32 (6) = 1 |
| 429 | |
465 | |
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|
466 | =item bool ecb_is_pot32 (uint32_t x) |
|
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467 | |
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468 | =item bool ecb_is_pot64 (uint32_t x) |
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469 | |
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470 | Return true iff C<x> is a power of two or C<x == 0>. |
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471 | |
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472 | For smaller types then C<uint32_t> you can safely use C<ecb_is_pot32>. |
|
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473 | |
| 430 | =item int ecb_ld32 (uint32_t x) |
474 | =item int ecb_ld32 (uint32_t x) |
| 431 | |
475 | |
| 432 | =item int ecb_ld64 (uint64_t x) |
476 | =item int ecb_ld64 (uint64_t x) |
| 433 | |
477 | |
| 434 | Returns the index of the most significant bit set in C<x>, or the number |
478 | Returns the index of the most significant bit set in C<x>, or the number |
| … | |
… | |
| 562 | for (i = 0; i < ecb_array_length (primes); i++) |
606 | for (i = 0; i < ecb_array_length (primes); i++) |
| 563 | sum += primes [i]; |
607 | sum += primes [i]; |
| 564 | |
608 | |
| 565 | =back |
609 | =back |
| 566 | |
610 | |
|
|
611 | =head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF |
| 567 | |
612 | |
|
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613 | These symbols need to be defined before including F<ecb.h> the first time. |
|
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614 | |
|
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615 | =over 4 |
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616 | |
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617 | =item ECB_NO_THRADS |
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618 | |
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619 | If F<ecb.h> is never used from multiple threads, then this symbol can |
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620 | be defined, in which case memory fences (and similar constructs) are |
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621 | completely removed, leading to more efficient code and fewer dependencies. |
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622 | |
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623 | Setting this symbol to a true value implies C<ECB_NO_SMP>. |
|
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624 | |
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625 | =item ECB_NO_SMP |
|
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626 | |
|
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627 | The weaker version of C<ECB_NO_THREADS> - if F<ecb.h> is used from |
|
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628 | multiple threads, but never concurrently (e.g. if the system the program |
|
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629 | runs on has only a single CPU with a single core, no hyperthreading and so |
|
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630 | on), then this symbol can be defined, leading to more efficient code and |
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631 | fewer dependencies. |
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632 | |
|
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633 | =back |
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634 | |
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635 | |
