sin()函数的函数原型在哪里，为何 cmath 中没有呢？

[lzxlzx777]

sin()函数的函数原型在哪里，为何 cmath 中没有呢？
以下是 cmath 的所有内容，我找不到 sin()函数原型呀，定义估计看不到，因为封装到库函数中了。但是函数原型在头文件中应该有吧，但是为何找不到呢？如何可以找到呢？

// cmath standard header

#if _MSC_VER > 1000
#pragma once
#endif

#ifndef _CMATH_
#define _CMATH_
#ifdef _STD_USING
#undef _STD_USING
#include <math.h>
#define _STD_USING
#else
#include <math.h>
#endif /* _STD_USING */
#endif /* _CMATH_ */

/*
* Copyright (c) 1994 by P.J. Plauger. ALL RIGHTS RESERVED.
* Consult your license regarding permissions and restrictions.
*/

[baihacker]

要注意，里面还包含了一个math.h

/***
*math.h - definitions and declarations for math library
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       This file contains constant definitions and external subroutine
*       declarations for the math subroutine library.
*       [ANSI/System V]
*
*       [Public]
*
****/

#ifndef _INC_MATH
#define _INC_MATH

#include <crtdefs.h>

#ifdef _MSC_VER
/*
 * Currently, all MS C compilers for Win32 platforms default to 8 byte
 * alignment.
 */
#pragma pack(push,_CRT_PACKING)
#endif  /* _MSC_VER */

#ifdef __cplusplus
extern "C" {
#endif  /* __cplusplus */

#ifndef __assembler

/* Definition of _exception struct - this struct is passed to the matherr
 * routine when a floating point exception is detected
 */

#ifndef _EXCEPTION_DEFINED
struct _exception {
        int type;       /* exception type - see below */
        char *name;     /* name of function where error occured */
        double arg1;    /* first argument to function */
        double arg2;    /* second argument (if any) to function */
        double retval;  /* value to be returned by function */
        } ;

#define _EXCEPTION_DEFINED
#endif  /* _EXCEPTION_DEFINED */


/* Definition of a _complex struct to be used by those who use cabs and
 * want type checking on their argument
 */

#ifndef _COMPLEX_DEFINED
struct _complex {
        double x,y; /* real and imaginary parts */
        } ;

#if !__STDC__ && !defined (__cplusplus)
/* Non-ANSI name for compatibility */
#define complex _complex
#endif  /* !__STDC__ && !defined (__cplusplus) */

#define _COMPLEX_DEFINED
#endif  /* _COMPLEX_DEFINED */
#endif  /* __assembler */


/* Constant definitions for the exception type passed in the _exception struct
 */

#define _DOMAIN     1   /* argument domain error */
#define _SING       2   /* argument singularity */
#define _OVERFLOW   3   /* overflow range error */
#define _UNDERFLOW  4   /* underflow range error */
#define _TLOSS      5   /* total loss of precision */
#define _PLOSS      6   /* partial loss of precision */

#define EDOM        33
#define ERANGE      34


/* Definitions of _HUGE and HUGE_VAL - respectively the XENIX and ANSI names
 * for a value returned in case of error by a number of the floating point
 * math routines
 */
#ifndef __assembler
#if !defined (_M_CEE_PURE)
_CRTIMP extern double _HUGE;
#else  /* !defined (_M_CEE_PURE) */
const double _HUGE = System::Double::PositiveInfinity;
#endif  /* !defined (_M_CEE_PURE) */
#endif  /* __assembler */

#define HUGE_VAL _HUGE

/* Function prototypes */

#if !defined (__assembler)
#ifndef _CRT_ABS_DEFINED
#define _CRT_ABS_DEFINED
        int     __cdecl abs(_In_ int _X);
        long    __cdecl labs(_In_ long _X);
#endif  /* _CRT_ABS_DEFINED */

        double  __cdecl acos(_In_ double _X);
        double  __cdecl asin(_In_ double _X);
        double  __cdecl atan(_In_ double _X);
        double  __cdecl atan2(_In_ double _Y, _In_ double _X);
#ifndef _SIGN_DEFINED
_Check_return_ _CRTIMP double __cdecl _copysign (_In_ double _Number, _In_ double _Sign);
_Check_return_ _CRTIMP double __cdecl _chgsign (_In_ double _X);
#define _SIGN_DEFINED
#endif  /* _SIGN_DEFINED */
        double  __cdecl cos(_In_ double _X);
        double  __cdecl cosh(_In_ double _X);
        double  __cdecl exp(_In_ double _X);
_CRT_JIT_INTRINSIC double  __cdecl fabs(_In_ double _X);
        double  __cdecl fmod(_In_ double _X, _In_ double _Y);
        double  __cdecl log(_In_ double _X);
        double  __cdecl log10(_In_ double _X);
        double  __cdecl pow(_In_ double _X, _In_ double _Y);
        double  __cdecl sin(_In_ double _X);
        double  __cdecl sinh(_In_ double _X);
        double  __cdecl tan(_In_ double _X);
        double  __cdecl tanh(_In_ double _X);
        double  __cdecl sqrt(_In_ double _X);
#ifndef _CRT_ATOF_DEFINED
#define _CRT_ATOF_DEFINED
_Check_return_ _CRTIMP double  __cdecl atof(_In_z_ const char *_String);
_Check_return_ _CRTIMP double  __cdecl _atof_l(_In_z_ const char *_String, _In_opt_ _locale_t _Locale);
#endif  /* _CRT_ATOF_DEFINED */

[mstlq]

std::sin()……

或者
using namespace std;
sin();

或者
using std::sin;
sin();

[TTOJJ]

好久没碰tc了~~帮顶,是不是在lib里???也可以不在头文件里的

[lzxlzx777]

double __cdecl log(_In_ double _X);
double __cdecl log10(_In_ double _X);
double __cdecl pow(_In_ double _X, _In_ double _Y);
double __cdecl sin(_In_ double _X);
double __cdecl sinh(_In_ double _X);
double __cdecl tan(_In_ double _X);
double __cdecl tanh(_In_ double _X);
double __cdecl sqrt(_In_ double _X);

以上加红的地方，是函数原型吗？
定义肯定看不到，但是原型应该能看到吧。因为我要声明它呀。

[baihacker]

[Quote=引用 4 楼 lzxlzx777 的回复:]
      double  __cdecl log(_In_ double _X);
        double  __cdecl log10(_In_ double _X);
        double  __cdecl pow(_In_ double _X, _In_ double _Y);
        double  __cdecl sin(_In_ double _X);
        double  __cdecl sinh(_In_ double _X);
        double  __cdecl tan(_In_ double _X);
        double  __cdecl tanh(_In_ double _X);
        double  __cdecl sqrt(_In_ double _X);

以上加红的地方，是函数原型吗？
定义肯定看不到，但是原型应该能看到吧。因为我要声明它呀。
[/Quote]
是的，这就是原型。

[whg01]

2楼正解。

[htzyhtzy]

[Quote=引用楼主 lzxlzx777 的回复:]
sin()函数的函数原型在哪里，为何 cmath 中没有呢？
以下是 cmath 的所有内容，我找不到 sin()函数原型呀，定义估计看不到，因为封装到库函数中了。但是函数原型在头文件中应该有吧，但是为何找不到呢？如何可以找到呢？

// cmath standard header

#if    _MSC_VER > 1000
#pragma once
#endif

#ifndef _CMATH_
#define _CMATH_
#ifdef _STD_USING
#undef _STD_USING
#include <math.h>
#define _STD_USING
#else
#include <math.h>
#endif /* _STD_USING */
#endif /* _CMATH_ */

/*
* Copyright (c) 1994 by P.J. Plauger.  ALL RIGHTS RESERVED.
* Consult your license regarding permissions and restrictions.
*/

[/Quote]

这句啊,头文件里包含另一个头文件，很多C++头文件 <cstdio>,<cstring>
#include <math.h>

[htzyhtzy]

很多C++头文件都是这样的