1.5. Data Definitions for libm

This section defines global identifiers and their values that are associated with interfaces contained in libm. These definitions are organized into groups that correspond to system headers. This convention is used as a convenience for the reader, and does not imply the existence of these headers, or their content.

These definitions are intended to supplement those provided in the referenced underlying specifications.

This specification uses ISO/IEC 9899 C Language as the reference programming language, and data definitions are specified in ISO C format. The C language is used here as a convenient notation. Using a C language description of these data objects does not preclude their use by other programming languages.

1.5.1. fenv.h

#define FE_INVALID	(1UL << 0)
#define FE_DIVBYZERO	(1UL << 2)
#define FE_OVERFLOW	(1UL << 3)
#define FE_UNDERFLOW	(1UL << 4)
#define FE_INEXACT	(1UL << 5)
#define FE_UNNORMAL	1UL << 1


#define FE_TONEAREST	0
#define FE_DOWNWARD	1
#define FE_UPWARD	2

typedef unsigned long int fexcept_t;

typedef unsigned long int fenv_t;
#define FE_DFL_ENV	((__const fenv_t *) 0xc009804c0270033fUL)

1.5.2. math.h

#define fpclassify(x)	(sizeof (x) == sizeof (float) ? __fpclassifyf (x) :sizeof (x) == sizeof (double) ? __fpclassify (x) : __fpclassifyl (x))
#define signbit(x)	(sizeof (x) == sizeof (float)? __signbitf (x): sizeof (x) == sizeof (double)? __signbit (x) : __signbitl (x))

#define FP_ILOGB0	-2147483648
#define FP_ILOGBNAN	2147483647