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The C and C++ Include Header Files

/usr/include/python3.12/pymath.h


$ cat -n /usr/include/python3.12/pymath.h

     1	// Symbols and macros to supply platform-independent interfaces to mathematical
     2	// functions and constants.
     3	
     4	#ifndef Py_PYMATH_H
     5	#define Py_PYMATH_H
     6	
     7	/* High precision definition of pi and e (Euler)
     8	 * The values are taken from libc6's math.h.
     9	 */
    10	#ifndef Py_MATH_PIl
    11	#define Py_MATH_PIl 3.1415926535897932384626433832795029L
    12	#endif
    13	#ifndef Py_MATH_PI
    14	#define Py_MATH_PI 3.14159265358979323846
    15	#endif
    16	
    17	#ifndef Py_MATH_El
    18	#define Py_MATH_El 2.7182818284590452353602874713526625L
    19	#endif
    20	
    21	#ifndef Py_MATH_E
    22	#define Py_MATH_E 2.7182818284590452354
    23	#endif
    24	
    25	/* Tau (2pi) to 40 digits, taken from tauday.com/tau-digits. */
    26	#ifndef Py_MATH_TAU
    27	#define Py_MATH_TAU 6.2831853071795864769252867665590057683943L
    28	#endif
    29	
    30	// Py_IS_NAN(X)
    31	// Return 1 if float or double arg is a NaN, else 0.
    32	#define Py_IS_NAN(X) isnan(X)
    33	
    34	// Py_IS_INFINITY(X)
    35	// Return 1 if float or double arg is an infinity, else 0.
    36	#define Py_IS_INFINITY(X) isinf(X)
    37	
    38	// Py_IS_FINITE(X)
    39	// Return 1 if float or double arg is neither infinite nor NAN, else 0.
    40	#define Py_IS_FINITE(X) isfinite(X)
    41	
    42	// Py_INFINITY: Value that evaluates to a positive double infinity.
    43	#ifndef Py_INFINITY
    44	#  define Py_INFINITY ((double)INFINITY)
    45	#endif
    46	
    47	/* Py_HUGE_VAL should always be the same as Py_INFINITY.  But historically
    48	 * this was not reliable and Python did not require IEEE floats and C99
    49	 * conformity.  Prefer Py_INFINITY for new code.
    50	 */
    51	#ifndef Py_HUGE_VAL
    52	#  define Py_HUGE_VAL HUGE_VAL
    53	#endif
    54	
    55	/* Py_NAN: Value that evaluates to a quiet Not-a-Number (NaN).  The sign is
    56	 * undefined and normally not relevant, but e.g. fixed for float("nan").
    57	 */
    58	#if !defined(Py_NAN)
    59	#    define Py_NAN ((double)NAN)
    60	#endif
    61	
    62	#endif /* Py_PYMATH_H */