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 搜索
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(自動存儲) 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)運算式) do double(雙精度浮點型) else enum(枚舉類型) extern(全局變量) float(浮點數(shù)) for fortran goto(goto語句) if(if語句) inline(行內(nèi)函式) int long(長整型) register(寄存器變量) restrict( restrict類型限定符) return short signed sizeof(sizeof運算符) 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) 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(對齊指定符) Alternative operators and tokens(替代運算符和令牌) 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) continue statement Declarations(聲明) do-while loop Enumerations(枚舉類型) Escape sequences(轉(zhuǎn)義字符) Expressions(表達式) External and tentative definitions(外部和暫定的定義) File scope(文件范圍) floating constant(浮點常量) 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(邏輯運算符) Lookup and name spaces Main function(主函式) Member access operators(會員接入運營商) Memory model Objects and alignment(字節(jié)對齊) Order of evaluation(評估順序) 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運算符) Statements(陳述) static assert declaration(靜態(tài)斷言聲明) Static storage duration(靜態(tài)存儲周期) Storage-class specifiers(存儲類說明符) 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(線程存儲時間) 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(日期和時間庫) difftime(計算兩個時間的間隔) gmtime gmtime_s localtime localtime_s mktime(將時間結(jié)構(gòu)數(shù)據(jù)轉(zhuǎn)換成經(jīng)過的秒數(shù)的函數(shù)) strftime(格式化輸出時間函數(shù)) time timespec timespec_get time_t tm wcsftime(格式化時間寬字符) Dynamic memory management aligned_alloc C memory management library(內(nèi)存管理庫) calloc free(釋放動態(tài)分配空間的函數(shù)) malloc(動態(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(錯誤報告) Error handling(錯誤處理) Error numbers(錯誤個數(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

為C抽象機器的目的定義計算機內(nèi)存存儲的語義。

C程序可用的數(shù)據(jù)存儲(內(nèi)存)是一個或多個連續(xù)的字節(jié)序列。內(nèi)存中的每個字節(jié)都有一個唯一的地址。

字節(jié)

字節(jié)是最小的可尋址內(nèi)存單元。它被定義為一個連續(xù)的位序列,足夠大以容納基本執(zhí)行字符集的任何成員(96個字符必須是單字節(jié))。C支持8位或更大的字節(jié)。

存儲和值表示的類型char,unsigned charsigned char使用一個字節(jié)。一個字節(jié)中的位數(shù)可以被訪問為CHAR_BIT。

內(nèi)存位置

存儲器位置是。

  • 標(biāo)量類型的對象(算術(shù)類型,指針類型,枚舉類型)

  • 或者是非零長度的最大的連續(xù)比特字段序列

struct S {
    char a;     // memory location #1
    int b : 5;  // memory location #2
    int c : 11, // memory location #2 (continued)          : 0,
        d : 8;  // memory location #3
    struct {
        int ee : 8; // memory location #4    } e;} obj; // The object 'obj' consists of 4 separate memory locations

線程和數(shù)據(jù)競爭執(zhí)行線程是程序中的一個控制流程,以thrd_create或其他方式調(diào)用頂級函數(shù)開始。任何線程都可能訪問程序中的任何對象(具有自動和線程本地存儲持續(xù)時間的對象仍然可以由另一個線程通過指針訪問)。不同的執(zhí)行線程總是被允許同時訪問(讀取和修改)不同的內(nèi)存位置,不會產(chǎn)生干擾,也不需要同步。(注意,如果在它們之間聲明的所有成員也是(非零長度)位字段,則同時更新同一結(jié)構(gòu)中的兩個非原子位字段是不安全的,不管這些介入位字段的大小如何,田野碰巧是)。當(dāng)表達式的評估寫入內(nèi)存位置并且另一個評估讀取或修改相同的內(nèi)存位置時,表達式被認為是沖突的。有兩個相互沖突的評估的程序除了兩者之外還有數(shù)據(jù)競爭。兩個沖突的評估都是原子操作沖突評估之一發(fā)生在另一個之前(請參閱memory_order)如果發(fā)生數(shù)據(jù)競爭,則程序的行為未定義。(特別是,mtx_unlock是與synchronized同步的,因此會在另一個線程的同一個互斥體的mtx_lock之前發(fā)生,這使得使用互斥鎖來防范數(shù)據(jù)爭奪成為可能)。內(nèi)存順序當(dāng)一個線程從一個線程讀取一個值內(nèi)存位置,它可能會看到初始值,寫入同一線程的值或?qū)懭肓硪粋€線程的值。

(自C11以來)

  • 兩個相互沖突的評估都是原子操作

  • 其中一個沖突評估發(fā)生在另一個之前(請參閱memory_order

如果發(fā)生數(shù)據(jù)競爭,程序的行為是未定義的。(特別mtx_unlock是。

另一個線程在同一個互斥體之前 mtx_lock進行同步并因此發(fā)生,這使得可以使用互斥鎖來防止數(shù)據(jù)競爭)內(nèi)存順序

當(dāng)線程從內(nèi)存位置讀取值時,它可能會看到初始值,寫入同一線程的值或?qū)懭肓硪粋€線程的值。請參閱有關(guān)memory_order線程寫入的順序?qū)ζ渌€程可見的詳細信息。

(since C11)

參考

  • C11 standard (ISO/IEC 9899:2011):

    • 3.6 byte (p: 4)

    • 3.14 memory location (p: 5)

    • 5.1.2.4 Multi-threaded executions and data races (p: 17-21)

  • C99 standard (ISO/IEC 9899:1999):

    • 3.6 byte (p: 4)

  • C89/C90 standard (ISO/IEC 9899:1990):

    • 1.6 DEFINITIONS OF TERMS

上一篇: 下一篇: