Top |

## Numerical DefinitionsNumerical Definitions — mathematical constants, and floating point decomposition |

## Types and Values

#define | G_IEEE754_FLOAT_BIAS |

#define | G_IEEE754_DOUBLE_BIAS |

union | GFloatIEEE754 |

union | GDoubleIEEE754 |

#define | G_E |

#define | G_LN2 |

#define | G_LN10 |

#define | G_PI |

#define | G_PI_2 |

#define | G_PI_4 |

#define | G_SQRT2 |

#define | G_LOG_2_BASE_10 |

## Description

GLib offers mathematical constants such as G_PI for the value of pi; many platforms have these in the C library, but some don't, the GLib versions always exist.

The GFloatIEEE754 and GDoubleIEEE754 unions are used to access the sign, mantissa and exponent of IEEE floats and doubles. These unions are defined as appropriate for a given platform. IEEE floats and doubles are supported (used for storage) by at least Intel, PPC and Sparc. See IEEE 754-2008 for more information about IEEE number formats.

## Types and Values

### G_IEEE754_FLOAT_BIAS

#define G_IEEE754_FLOAT_BIAS (127)

The bias by which exponents in single-precision floats are offset.

### G_IEEE754_DOUBLE_BIAS

#define G_IEEE754_DOUBLE_BIAS (1023)

The bias by which exponents in double-precision floats are offset.

### union GFloatIEEE754

The GFloatIEEE754 and GDoubleIEEE754 unions are used to access the sign, mantissa and exponent of IEEE floats and doubles. These unions are defined as appropriate for a given platform. IEEE floats and doubles are supported (used for storage) by at least Intel, PPC and Sparc.

### union GDoubleIEEE754

The GFloatIEEE754 and GDoubleIEEE754 unions are used to access the sign, mantissa and exponent of IEEE floats and doubles. These unions are defined as appropriate for a given platform. IEEE floats and doubles are supported (used for storage) by at least Intel, PPC and Sparc.

### G_LN2

#define G_LN2 0.69314718055994530941723212145817656807550013436026

The natural logarithm of 2.

### G_LN10

#define G_LN10 2.3025850929940456840179914546843642076011014886288

The natural logarithm of 10.

### G_PI

#define G_PI 3.1415926535897932384626433832795028841971693993751

The value of pi (ratio of circle's circumference to its diameter).