亚洲国产日韩欧美一区二区三区,精品亚洲国产成人av在线,国产99视频精品免视看7,99国产精品久久久久久久成人热,欧美日韩亚洲国产综合乱

目錄 搜尋
Algorithms Algorithms(算法) bsearch bsearch_s qsort qsort_s Atomic operations Atomic operations library(原子操作庫) ATOMIC_*_LOCK_FREE atomic_compare_exchange_strong atomic_compare_exchange_strong_explicit atomic_compare_exchange_weak atomic_compare_exchange_weak_explicit atomic_exchange atomic_exchange_explicit atomic_fetch_add atomic_fetch_add_explicit atomic_fetch_and atomic_fetch_and_explicit atomic_fetch_or atomic_fetch_or_explicit atomic_fetch_sub atomic_fetch_sub_explicit atomic_fetch_xor atomic_fetch_xor_explicit atomic_flag atomic_flag_clear atomic_flag_clear_explicit ATOMIC_FLAG_INIT atomic_flag_test_and_set atomic_flag_test_and_set_explicit atomic_init atomic_is_lock_free atomic_load atomic_load_explicit atomic_signal_fence atomic_store atomic_store_explicit atomic_thread_fence(線程圍欄) ATOMIC_VAR_INIT kill_dependency memory_order(內(nèi)存排序) C keywords auto(自動(dòng)存儲(chǔ)) break(跳出循環(huán)) C keywords(關(guān)鍵詞) case char const(常量修飾符) continue default(預(yù)設(shè)運(yùn)算式) do double(雙精度浮點(diǎn)型) else enum(枚舉類型) extern(全局變量) float(浮點(diǎn)數(shù)) for fortran goto(goto語句) if(if語句) inline(行內(nèi)函式) int long(長(zhǎng)整型) register(寄存器變量) restrict( restrict類型限定符) return short signed sizeof(sizeof運(yùn)算符) static(靜態(tài)變量) struct(結(jié)構(gòu)體) switch(switch語句) typedef(typedef關(guān)鍵字) union(聯(lián)合體) unsigned(無符號(hào)) void(空類型) volatile(volatile變量) while(while語句) _Alignas _Alignof _Atomic _Bool _Complex _Generic _Imaginary _Noreturn _Static_assert _Thread_local C language #define directive #elif directive #else directive #endif directive #error directive #if directive #ifdef directive #ifndef directive #include directive #line directive #pragma directive alignas(對(duì)齊指定符) Alternative operators and tokens(替代運(yùn)算符和令牌) Analyzability Arithmetic operators Arithmetic types Array declaration(數(shù)組聲明) Array initialization(陣列初始化) ASCII Chart Assignment operators(賦值運(yùn)算符) types(atomic類型限定符) Basic concepts Bit fields(位域) break statement C language C Operator Precedence cast operator character constant(字符字面量) Comments(注釋符) Comparison operators(比較運(yùn)算符) compound literals(符合字面量) Conditional inclusion(條件包含) Conformance(一致性) const type qualifier(const 限定符) Constant expressions(常量表達(dá)) continue statement Declarations(聲明) do-while loop Enumerations(枚舉類型) Escape sequences(轉(zhuǎn)義字符) Expressions(表達(dá)式) External and tentative definitions(外部和暫定的定義) File scope(文件范圍) floating constant(浮點(diǎn)常量) for loop Function declarations(函數(shù)聲明) Function definitions(函數(shù)聲明) Functions Generic selection泛型選擇 goto statement Identifier(標(biāo)示符) if statement Implicit conversions(隱式轉(zhuǎn)換) Increment/decrement operators(前置/后置操作符) Initialization(初始化) inline function specifier(內(nèi)聯(lián)函式) integer constant Lifetime(生命期) Logical operators(邏輯運(yùn)算符) Lookup and name spaces Main function(主函式) Member access operators(會(huì)員接入運(yùn)營(yíng)商) Memory model Objects and alignment(字節(jié)對(duì)齊) Order of evaluation(評(píng)估順序) Other operators Phases of translation(翻譯階段) Pointer declaration Preprocessor(預(yù)處理) restrict type qualifier(restrict類型限定符) return statement Scalar initialization(標(biāo)量類型初始化) Scope(范圍) sizeof operator(sizeof運(yùn)算符) Statements(陳述) static assert declaration(靜態(tài)斷言聲明) Static storage duration(靜態(tài)存儲(chǔ)周期) Storage-class specifiers(存儲(chǔ)類說明符) string literals(字符串字面量) Struct and union initialization(結(jié)構(gòu)體與聯(lián)合體初始化) Struct declaration(結(jié)構(gòu)體聲明) switch statement Thread storage duration(線程存儲(chǔ)時(shí)間) Type Type(類型) Typedef declaration(Typedef聲明) Undefined behavior(未定義行為) Union declaration(聯(lián)合體聲明) Value categories(值類別) Variadic arguments(變長(zhǎng)參數(shù)宏) volatile type qualifier(volatile 類型限定符) while loop _Alignof operator _Noreturn function specifier Date and time asctime(asctime函數(shù)) asctime_s clock CLOCKS_PER_SEC clock_t ctime(ctime函數(shù)) ctime_s Date and time utilities(日期和時(shí)間庫) difftime(計(jì)算兩個(gè)時(shí)間的間隔) gmtime gmtime_s localtime localtime_s mktime(將時(shí)間結(jié)構(gòu)數(shù)據(jù)轉(zhuǎn)換成經(jīng)過的秒數(shù)的函數(shù)) strftime(格式化輸出時(shí)間函數(shù)) time timespec timespec_get time_t tm wcsftime(格式化時(shí)間寬字符) Dynamic memory management aligned_alloc C memory management library(內(nèi)存管理庫) calloc free(釋放動(dòng)態(tài)分配空間的函數(shù)) malloc(動(dòng)態(tài)分配內(nèi)存空間的函數(shù)) realloc(重新分配內(nèi)存空間的函數(shù)) Error handling abort_handler_s assert(斷言) constraint_handler_t errno(錯(cuò)誤報(bào)告) Error handling(錯(cuò)誤處理) Error numbers(錯(cuò)誤個(gè)數(shù)) ignore_handler_s set_constraint_handler_s static_assert File input/output clearerr(清除/復(fù)位) fclose feof ferror fflush(清空文件緩沖區(qū)) fgetc fgetpos fgets fgetwc fgetws File input/output fopen fopen_s fprintf fprintf_s fputc fputs fputwc fputws fread freopen freopen_s fscanf fscanf_s fseek fsetpos ftell fwide fwprintf fwprintf_s fwrite fwscanf fwscanf_s getc getchar gets gets_s getwchar perror printf printf_s putc putchar puts putwc putwchar remove rename rewind scanf scanf_s setbuf setvbuf snprintf sprintf sscanf sscanf_s swprintf swprintf_s swscanf swscanf_s tmpfile tmpfile_s tmpnam tmpnam_s ungetc ungetwc vfprintf vfprintf_s vfscanf vfscanf_s vfwprintf vfwprintf_s vfwscanf vfwscanf_s vprintf vprintf_s vscanf vscanf_s vsnprintf vsprintf vsscanf vsscanf_s vswprintf vswprintf_s vswscanf vswscanf_s vwprintf vwprintf_s vwscanf vwscanf_s wprintf wprintf_s wscanf wscanf_s Localization support lconv LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME localeconv Localization support setlocale Numerics abs acos acosf acosh acoshf acoshl acosl asin asinf asinh asinhf asinhl asinl atan atan2 atan2f atan2l atanf atanh atanhf atanhl atanl cabs cabsf cabsl cacos cacosf cacosh cacoshf cacoshl cacosl carg cargf cargl casin casinf casinh casinhf casinhl casinl catan catanf catanh catanhf catanhl catanl cbrt cbrtf cbrtl ccos ccosf ccosh ccoshf ccoshl ccosl ceil ceilf ceill cexp cexpf cexpl cimag cimagf cimagl clog clogf clogl CMPLX CMPLXF CMPLXL Common mathematical functions complex Complex number arithmetic conj conjf conjl copysign copysignf copysignl cos cosf cosh coshf coshl cosl cpow cpowf cpowl cproj cprojf cprojl creal crealf creall csin csinf csinh csinhf csinhl csinl csqrt csqrtf csqrtl ctan ctanf ctanh ctanhf ctanhl ctanl div double_t erf erfc erfcf erfcl erff erfl exp exp2 exp2f exp2l expf expl expm1 expm1f expm1l fabs fabsf fabsl fdim feclearexcept fegetenv fegetexceptflag fegetround feholdexcept feraiseexcept fesetenv fesetexceptflag fesetround fetestexcept feupdateenv FE_ALL_EXCEPT FE_DFL_ENV FE_DIVBYZERO FE_DOWNWARD FE_INEXACT FE_INVALID FE_OVERFLOW FE_TONEAREST FE_TOWARDZERO FE_UNDERFLOW FE_UPWARD Floating-point environment float_t floor floorf floorl fma fmaf fmal fmax fmaxf fmaxl fmin fminf fminl fmod fmodf fmodl fpclassify FP_INFINITE FP_NAN FP_NORMAL FP_SUBNORMAL FP_ZERO frexp frexpf frexpl HUGE_VAL HUGE_VALF HUGE_VALL hypot hypotf hypotl I ilogb ilogbf ilogbl imaginary imaxabs imaxdiv INFINITY isfinite isgreater isgreaterequal isinf isless islessequal islessgreater isnan isnormal isunordered labs ldexp ldexpf ldexpl ldiv lgamma lgammaf lgammal llabs lldiv llrint llrintf llrintl llround llroundf llroundl log log10 log10f log10l log1p log1pf log1pl log2 log2f log2l logb logbf logbl logf logl lrint lrintf lrintl lround lroundf lroundl MATH_ERREXCEPT math_errhandling MATH_ERRNO modf modff modfl nan NAN nanf nanl nearbyint nearbyintf nearbyintl nextafter nextafterf nextafterl nexttoward nexttowardf nexttowardl Numerics pow powf powl Pseudo-random number generation rand RAND_MAX remainder remainderf remainderl remquo remquof remquol rint rintf rintl round roundf roundl scalbln scalblnf scalblnl scalbn scalbnf scalbnl signbit sin sinf sinh sinhf sinhl sinl sqrt sqrtf sqrtl srand tan tanf tanh tanhf tanhl tanl tgamma tgammaf tgammal trunc truncf truncl Type-generic math _Complex_I _Imaginary_I Program support abort atexit at_quick_exit exit EXIT_FAILURE EXIT_SUCCESS getenv getenv_s jmp_buf longjmp Program support utilities quick_exit raise setjmp SIGABRT SIGFPE SIGILL SIGINT signal SIGSEGV SIGTERM sig_atomic_t SIG_DFL SIG_ERR SIG_IGN system _Exit Strings atof atoi atol atoll btowc c16rtomb c32rtomb char16_t char32_t isalnum isalpha isblank iscntrl isdigit isgraph islower isprint ispunct isspace isupper iswalnum iswalpha iswblank iswcntrl iswctype iswdigit iswgraph iswlower iswprint iswpunct iswspace iswupper iswxdigit isxdigit mblen mbrlen mbrtoc16 mbrtoc32 mbrtowc mbsinit mbsrtowcs mbsrtowcs_s mbstate_t mbstowcs mbstowcs_s mbtowc memchr memcmp memcpy memcpy_s memmove memmove_s memset memset_s Null-terminated byte strings Null-terminated multibyte strings Null-terminated wide strings strcat strcat_s strchr strcmp strcoll strcpy strcpy_s strcspn strerror strerrorlen_s strerror_s Strings library strlen strncat Thread support call_once cnd_broadcast cnd_destroy cnd_init cnd_signal cnd_timedwait cnd_wait mtx_destroy mtx_init mtx_lock mtx_plain mtx_recursive mtx_timed mtx_timedlock mtx_trylock mtx_unlock once_flag ONCE_FLAG_INIT thrd_busy thrd_create thrd_current thrd_detach thrd_equal thrd_error thrd_exit thrd_join thrd_nomem thrd_sleep thrd_success thrd_timedout thrd_yield Thread support library thread_local tss_create tss_delete TSS_DTOR_ITERATIONS tss_get tss_set Type support Boolean type support library Fixed width integer types FLT_EVAL_METHOD FLT_ROUNDS max_align_t NULL Numeric limits offsetof ptrdiff_t size_t Type support Variadic functions Variadic functions va_arg va_copy va_end va_list va_start
文字

(包括函數(shù)調(diào)用表達(dá)式中函數(shù)參數(shù)的評(píng)估順序,以及任何表達(dá)式中子表達(dá)式的評(píng)估順序)的任何C運(yùn)算符的操作數(shù)的評(píng)估順序是未指定的(除非在下面指出)。編譯器將以任何順序?qū)λ鼈冞M(jìn)行評(píng)估,并且可以在再次評(píng)估同一個(gè)表達(dá)式時(shí)選擇另一個(gè)順序。

在C中沒有從左到右或從右到左的評(píng)估概念,這不應(yīng)該與操作符的從左到右和從右到左的關(guān)聯(lián)性相混淆:表達(dá)式f1() + f2() + f3()被解析為(f1() + f2()) + f3()由于左operator +的從右到關(guān)聯(lián)性,但函數(shù)調(diào)用f3可以在運(yùn)行時(shí)首先,最后或之間f1()f2()在運(yùn)行時(shí)進(jìn)行評(píng)估。

定義

評(píng)估

編譯器對(duì)每個(gè)表達(dá)式或子表達(dá)式執(zhí)行兩種評(píng)估(兩者都是可選的):

  • 值計(jì)算:計(jì)算表達(dá)式返回的值。這可能涉及確定對(duì)象的身份(左值評(píng)估)或讀取先前分配給對(duì)象的值(右值評(píng)估)

  • 副作用:訪問(讀取或?qū)懭耄┯梢鬃兊淖笾抵付ǖ膶?duì)象,修改(寫入)對(duì)象,原子同步(自C11起),修改文件,修改浮點(diǎn)環(huán)境(如果支持)或調(diào)用一個(gè)執(zhí)行任何這些操作的函數(shù)。

如果表達(dá)式不產(chǎn)生副作用,并且編譯器可以確定該值未被使用,則表達(dá)式可能不會(huì)被評(píng)估。

排序

“sequenced-before”是同一線程內(nèi)的評(píng)估之間的不對(duì)稱,傳遞,成對(duì)關(guān)系(如果涉及原子類型和內(nèi)存障礙,它可以跨線程延伸)。

  • 如果一個(gè)序列點(diǎn)存在于子表達(dá)式E1和E2之間,那么E1的值計(jì)算和副作用都被排序 - 在 E2的每個(gè)值計(jì)算和副作用之前

如果在評(píng)估B之前對(duì)評(píng)估A進(jìn)行排序,那么在開始評(píng)估B之前評(píng)估A將會(huì)完成。如果A在B之前未被測(cè)序,而B在A之前被測(cè)序,那么在評(píng)估A開始之前B的評(píng)估將完成。如果A不B之前測(cè)序和B不是A之前測(cè)序,然后兩種可能性存在:A,B的評(píng)價(jià)是未測(cè)序:它們可以以任何順序執(zhí)行,并且可以重疊(單個(gè)執(zhí)行線程內(nèi),編譯器可以交織包含A和B)的A和B評(píng)估的CPU指令是不確定地排序的:它們可以以任何順序執(zhí)行但可能不重疊:A在B之前將是完整的,或者B將在A之前完成。在下一次評(píng)估同一個(gè)表達(dá)式時(shí)是相反的。

(自C11以來)

  • 如果在評(píng)估B之前對(duì)評(píng)估A進(jìn)行排序,那么在開始評(píng)估B之前評(píng)估A將會(huì)完成。

  • 如果A在B之前未被測(cè)序,而B在A之前被測(cè)序,那么在評(píng)估A開始之前B的評(píng)估將完成。

  • 如果A在B和B未在A之前排序之前未被測(cè)序,則存在兩種可能性:

    • A和B的評(píng)估是不確定的:它們可以以任何順序執(zhí)行并且可以重疊(在單個(gè)執(zhí)行線程內(nèi),編譯器可以交織包括A和B的CPU指令)

    • A和B的評(píng)估是不確定地排序的:它們可以以任何順序執(zhí)行但可能不重疊:A會(huì)在B之前完成,或B在A之前完成。順序可能與下次相同表達(dá)式相反被評(píng)估。

(since C11)

規(guī)則

1)評(píng)估所有函數(shù)參數(shù)和函數(shù)指示符后,以及實(shí)際函數(shù)調(diào)用之前,有一個(gè)序列點(diǎn)。

2)在評(píng)估第一個(gè)(左)操作數(shù)之后以及評(píng)估以下二元運(yùn)算符的第二個(gè)(右)操作數(shù)之前,有一個(gè)序列點(diǎn):( &&邏輯AND),||(邏輯OR)和,(逗號(hào))。

3)在評(píng)估第一個(gè)(左)操作數(shù)之后并且在評(píng)估第二個(gè)或第三個(gè)操作數(shù)(以評(píng)估者為準(zhǔn))之前有一個(gè)序列點(diǎn), ?:

4)在完整表達(dá)式(表達(dá)式不是子表達(dá)式:通常是以分號(hào)或if / switch / while / do的控制語句結(jié)束的表達(dá)式)和下一個(gè)完整表達(dá)式之前有一個(gè)序列點(diǎn)。

5)完整聲明的結(jié)尾處有一個(gè)序列點(diǎn)。6)在函數(shù)返回之前有一個(gè)序列點(diǎn)。7)在格式化I / O中的每個(gè)轉(zhuǎn)換說明符相關(guān)的動(dòng)作之后有一個(gè)序列點(diǎn)(特別是,對(duì)于scanf將不同的字段寫入同一變量以及用于讀取和修改或修改相同變量的printf變量不止一次使用%n)8)在每次調(diào)用庫函數(shù)qsort和bsearch所做的比較函數(shù)之前以及之后,以及任何對(duì)比較函數(shù)的調(diào)用和關(guān)聯(lián)對(duì)象的移動(dòng)之間都有序列點(diǎn)由qsort制作

(自C99以來)

9)操作數(shù)對(duì)任何操作符的值計(jì)算(但不是副作用)在操作符結(jié)果的值計(jì)算之前(但不包括其副作用)排序。10)直接賦值運(yùn)算符和所有復(fù)合賦值運(yùn)算符的副作用(左變?cè)男薷模┰谧蠛陀覂蓚€(gè)參數(shù)的值計(jì)算(但不是副作用)之后排序。11)后增量和后減算子的值計(jì)算在其副作用之前被排序。12)在另一個(gè)函數(shù)調(diào)用之前或之后未被排序的函數(shù)調(diào)用被不確定地排序(構(gòu)成不同函數(shù)調(diào)用的CPU指令不能交錯(cuò),即使函數(shù)被內(nèi)聯(lián))13)在初始化列表表達(dá)式中,

(自C11以來)

未定義的行為

1)如果對(duì)標(biāo)量對(duì)象的副作用相對(duì)于同一標(biāo)量對(duì)象上的另一副作用而言是不確定的,則行為是不確定的。

i = ++i + i++; // undefined behaviori = i++ + 1; // undefined behaviorf(++i, ++i); // undefined behaviorf(i = -1, i = -1); // undefined behavior

2)如果標(biāo)量對(duì)象的副作用相對(duì)于使用相同標(biāo)量對(duì)象的值進(jìn)行值計(jì)算而言是未定序的,則行為是未定義的。

f(i, i++); // undefined behaviora[i] = i++; // undefined bevahior

3)只要子表達(dá)式的至少一個(gè)允許排序允許這樣一個(gè)不確定的副作用,上述規(guī)則就適用。

上一篇: 下一篇: