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#ifndef CYGONCE_LIBM_MATH_H
#define CYGONCE_LIBM_MATH_H
//===========================================================================
//
//      math.h
//
//      Standard mathematical functions conforming to ANSI and other standards
//
//===========================================================================
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//####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   jlarmour
// Contributors:  jlarmour
// Date:        1998-02-13
// Purpose:     
// Description: Standard mathematical functions. These can be
//              configured to conform to ANSI section 7.5. There are also
//              a number of extensions conforming to IEEE-754 and behaviours
//              compatible with other standards
// Usage:       #include <math.h>
//
//####DESCRIPTIONEND####
//
//===========================================================================
 
// CONFIGURATION
 
#include <pkgconf/libm.h>   // Configuration header
 
// Include the Math library?
#ifdef CYGPKG_LIBM     
 
// INCLUDES
 
#include <cyg/infra/cyg_type.h>    // Common type definitions and support
#include <float.h>                 // Properties of FP representation on this
                                   // platform
#include <sys/ieeefp.h>            // Cyg_libm_ieee_double_shape_type
 
// CONSTANT DEFINITIONS
 
 
// HUGE_VAL is a positive double (not necessarily representable as a float)
// representing infinity as specified in ANSI 7.5. cyg_libm_infinity is
// defined further down
#define HUGE_VAL        (cyg_libm_infinity.value)
 
 
#ifndef CYGSYM_LIBM_NO_XOPEN_SVID_NAMESPACE_POLLUTION
// HUGE is defined in System V Interface Definition 3 (SVID3) as the largest
// finite single precision number
#define HUGE            FLT_MAX    // from float.h
 
 
// Values used in the type field of struct exception below
 
#define DOMAIN          1
#define SING            2
#define OVERFLOW        3
#define UNDERFLOW       4
#define TLOSS           5
#define PLOSS           6
 
 
// TYPE DEFINITIONS
 
// Things required to support matherr() ( see comments in <pkgconf/libm.h>)
 
struct exception {
    int type;       // One of DOMAIN, SING, OVERFLOW, UNDERFLOW, TLOSS, PLOSS
    char *name;     // Name of the function generating the exception
    double arg1;    // First argument to the function
    double arg2;    // Second argument to the function
    double retval;  // Value to be returned - can be altered by matherr()
};
 
#endif // ifndef CYGSYM_LIBM_NO_XOPEN_SVID_NAMESPACE_POLLUTION
 
 
// GLOBALS
 
externC const Cyg_libm_ieee_double_shape_type cyg_libm_infinity;
 
//===========================================================================
// FUNCTION PROTOTYPES
 
// Functions not part of a standard
 
// This retrieves a pointer to the current compatibility mode of the Math
// library. See <pkgconf/libm.h> for the definition of Cyg_libm_compat_t
 
#ifdef CYGSEM_LIBM_THREAD_SAFE_COMPAT_MODE
 
externC Cyg_libm_compat_t
cyg_libm_get_compat_mode( void );
 
externC Cyg_libm_compat_t
cyg_libm_set_compat_mode( Cyg_libm_compat_t );
 
#else
 
externC Cyg_libm_compat_t cygvar_libm_compat_mode;
 
// Defined as static inline as it is unlikely that anyone wants to take the
// address of these functions.
//
// This returns the current compatibility mode
 
static inline Cyg_libm_compat_t
cyg_libm_get_compat_mode( void )
{
    return cygvar_libm_compat_mode;
}
 
// This sets the compatibility mode, and returns the previous mode
static inline Cyg_libm_compat_t
cyg_libm_set_compat_mode( Cyg_libm_compat_t math_compat_mode)
{
    Cyg_libm_compat_t oldmode;
 
    oldmode = cygvar_libm_compat_mode;
    cygvar_libm_compat_mode = math_compat_mode;
    return oldmode;
}
 
#endif // ifdef CYGSEM_LIBM_THREAD_SAFE_COMPAT_MODE
 
#ifdef CYGSEM_LIBM_THREAD_SAFE_GAMMA_FUNCTIONS
 
// FIXME: these need to be documented and signgam mentioned as non-ISO
// This returns the address of the signgam variable used by the gamma*() and
// lgamma*() functions
externC int *
cyg_libm_get_signgam_p( void );
 
#define signgam (*cyg_libm_get_signgam_p())
 
#else
 
externC int signgam;
 
#endif // ifdef CYGSEM_LIBM_THREAD_SAFE_GAMMA_FUNCTIONS
 
//===========================================================================
// Standard ANSI functions. Angles are always in radians
 
// Trigonometric functions - ANSI 7.5.2
 
externC double
acos( double );            // arc cosine i.e. inverse cos
 
externC double
asin( double );            // arc sine i.e. inverse sin
 
externC double
atan( double );            // arc tan i.e. inverse tan
 
externC double
atan2( double, double );   // arc tan of (first arg/second arg) using signs
                           // of args to determine quadrant
 
externC double
cos( double );             // cosine
 
externC double
sin( double );             // sine
 
externC double
tan( double );             // tangent
 
// Hyperbolic functions - ANSI 7.5.3
 
externC double
cosh( double );            // hyperbolic cosine
 
externC double
sinh( double );            // hyperbolic sine
 
externC double
tanh( double );            // hyperbolic tangent
 
// Exponential and Logarithmic Functions - ANSI 7.5.4
 
externC double
exp( double );             // exponent
 
externC double
frexp( double, int * );    // break number into normalized fraction (returned)
                           // and integral power of 2 (second arg)
 
externC double
ldexp( double, int );      // multiples number by integral power of 2 
 
externC double
log( double );             // natural logarithm
 
externC double
log10( double );           // base ten logarithm
 
externC double
modf( double, double * );  // break number into integral and fractional
                           // parts, each of which has same sign as arg.
                           // It returns signed fractional part, and
                           // puts integral part in second arg
 
// Power Functions - ANSI 7.5.5
 
externC double
pow( double, double );     // (1st arg) to the power of (2nd arg)
 
externC double
sqrt( double );            // square root
 
// Nearest integer, absolute value and remainder functions - ANSI 7.5.6
 
externC double
ceil( double );            // smallest integer >= arg
 
externC double
fabs( double );            // absolute value
 
externC double
floor( double );           // largest integer <= arg
 
externC double
fmod( double, double );    // remainder of (1st arg)/(2nd arg)
 
//===========================================================================
// Other standard functions
 
#ifndef CYGSYM_LIBM_NO_XOPEN_SVID_NAMESPACE_POLLUTION
externC int
matherr( struct exception * );    // User-overridable error handling - see
#endif                            // <pkgconf/libm.h> for a discussion
 
// FIXME: from here needs to be documented and mentioned as non-ISO
// Arc Hyperbolic trigonometric functions
 
externC double
acosh( double );                  // Arc hyperbolic cos i.e. inverse cosh
 
externC double
asinh( double );                  // Arc hyperbolic sin i.e. inverse sinh
 
externC double
atanh( double );                  // Arc hyperbolic tan i.e. inverse tanh
 
// Error functions
 
externC double                    // Error function, such that
erf( double );                    // erf(x) = 2/sqrt(pi) * integral from
                                  // 0 to x of e**(-t**2) dt
 
externC double                    // Complementary error function - simply
erfc( double );                   // 1.0 - erf(x)
 
// Gamma functions
 
externC double                    // Logarithm of the absolute value of the
lgamma( double );                 // gamma function of the argument. The
                                  // integer signgam is used to store the
                                  // sign of the gamma function of the arg
 
externC double
lgamma_r( double, int * );        // Re-entrant version of the above, where
                                  // the user passes the location of signgam
                                  // as the second argument
 
externC double                    // Identical to lgamma()!
gamma( double );                  // The reasons for this are historical,
                                  // and may be changed in future standards
                                  //
                                  // To get the real gamma function, you should
                                  // use: l=lgamma(x); g=signgam*exp(l);
                                  //
                                  // Do not just do signgam*exp(lgamma(x))
                                  // as lgamma() modifies signgam
 
externC double
gamma_r( double, int * );         // Identical to lgamma_r(). See above.
 
 
// Bessel functions
 
externC double                    // Zero-th order Bessel function of the
j0( double );                     // first kind at the ordinate of the argument
 
externC double                    // First-order Bessel function of the
j1( double );                     // first kind at the ordinate of the argument
 
externC double                    // Bessel function of the first kind of the
jn( int, double );                // order of the first argument at the
                                  // ordinate of the second argument
 
externC double                    // Zero-th order Bessel function of the
y0( double );                     // second kind at the ordinate of the
                                  // argument
 
externC double                    // First-order Bessel function of the
y1( double );                     // second kind at the ordinate of the
                                  // argument
 
externC double                    // Bessel function of the second kind of the
yn( int, double );                // order of the first argument at the
                                  // ordinate of the second argument
 
// scalb*()
 
externC double                    // scalbn(x,n) returns x*(2**n)
scalbn( double, int );
 
#ifdef CYGFUN_LIBM_SVID3_scalb
 
externC double
scalb( double, double );          // as above except n is a floating point arg
 
#else
externC double
scalb( double, int );             // as scalbn()
 
#endif // ifdef CYGFUN_LIBM_SVID3_scalb
 
// And the rest
 
externC double
cbrt( double );                   // Cube Root
 
externC double                    // hypotenuse function, defined such that:
hypot( double, double );          // hypot(x,y)==sqrt(x**2 + y**2)
 
externC int                       // whether the argument is NaN
isnan( double );
 
externC int
finite( double );                 // whether the argument is finite
 
externC double                    // logb returns the binary exponent of its
logb( double );                   // argument as an integral value
                                  // This is not recommended - use ilogb
                                  // instead
 
externC int                       // As for logb, but has the more correct
ilogb( double );                  // return value type of int
 
 
externC double                    // nextafter(x,y) returns the next
nextafter( double, double );      // representable floating point number
                                  // adjacent to x in the direction of y
                                  // i.e. the next greater FP if y>x, the next
                                  // less FP if y<x, or just x if y==x
 
externC double                    // remainder(x,y) returns the remainder
remainder( double, double );      // when x is divided by y
 
externC double                    // IEEE Test Vector
significand( double );            // significand(x) computes:
                                  //   scalb(x, (double) -ilogb(x))
 
//===========================================================================
// Non-standard functions
 
externC double                    // copysign(x,y) returns a number with
copysign ( double, double );      // the absolute value of x and the sign of y
 
externC double                    // rounds to an integer according to the
rint( double );                   // current rounding mode
 
 
// BSD functions
 
externC double                    // expm1(x) returns the equivalent of
expm1( double );                  // (exp(x) - 1) but more accurately when
                                  // x tends to zero
 
externC double                    // log1p(x) returns the equivalent of
log1p( double );                  // log(1+x) but more accurately when
                                  // x tends to zero
 
#endif // ifdef CYGPKG_LIBM     
 
#endif // CYGONCE_LIBM_MATH_H multiple inclusion protection
 
// EOF math.h