Floating-Point Support
Many Microsoft run-time library functions require floating-point support from a math coprocessor or from the floating-point libraries that accompany the compiler. Floating-point support functions are loaded only if required.
When you use a floating-point type specifier in the format string of a call to a function in the printf or scanf family, you must specify a floating-point value or a pointer to a floating-point value in the argument list to tell the compiler that floating-point support is required.
Floating-point precision of intermediate values is controlled by the _controlfp. By default, _controlfp's precision control is set to 53 bits (_PC_53). Linking with FP10.OBJ changes the default precision control to 64 bits (_PC_64). On the linker command line, FP10.OBJ must appear before LIBC.LIB, LIBCMT.LIB, or MSVCRT.LIB.
Floating-Point Functions
| Routine | Use |
|---|---|
| abs | Return absolute value of int |
| acos, acosf | Calculate arccosine |
| asin, asinf | Calculate arcsine |
| atan, atanf, atan2, atan2f | Calculate arctangent |
| atof | Convert character string to double-precision floating-point value |
| Bessel functions | Calculate Bessel functions _j0, _j1, _jn, _y0, _y1, _yn |
| _cabs | Find absolute value of complex number |
| ceil, ceilf | Find integer ceiling |
| _chgsign | Reverse sign of double-precision floating-point argument |
| _clear87, _clearfp | Get and clear floating-point status word |
| _control87, _controlfp | Get old floating-point control word and set new control-word value |
| _copysign | Return one value with sign of another |
| cos, cosf, cosh, coshf | Calculate cosine |
| difftime | Compute difference between two specified time values |
| div | Divide one integer by another, returning quotient and remainder |
| _ecvt | Convert double to character string of specified length |
| exp, expf | Calculate exponential function |
| fabs, fabsf | Find absolute value |
| _fcvt | Convert double to string with specified number of digits following decimal point |
| _finite | Determine whether given double-precision floating-point value is finite |
| floor, floorf | Find largest integer less than or equal to argument |
| fmod, fmodf | Find floating-point remainder |
| _fpclass | Return status word containing information on floating-point class |
| _fpieee_flt | Invoke user-defined trap handler for IEEE floating-point exceptions |
| _fpreset | Reinitialize floating-point math package |
| frexp | Calculate exponential value |
| _gcvt | Convert floating-point value to character string |
| _hypot, hypotf | Calculate hypotenuse of right triangle |
| _isnan | Check given double-precision floating-point value for not a number (NaN) |
| labs | Return absolute value of long |
| ldexp | Calculate product of argument and 2 to specified power |
| ldiv | Divide one long integer by another, returning quotient and remainder |
| log, logf, log10, log10f | Calculate natural or base-10 logarithm. |
| _logb | Extract exponential value of double-precision floating-point argument |
| _lrotl, _lrotr | Shift unsigned long int left (_lrotl) or right (_lrotr) |
| _matherr | Handle math errors |
| __max | Return larger of two values |
| __min | Return smaller of two values |
| modf, modff | Split argument into integer and fractional parts |
| _nextafter | Return next representable neighbor |
| pow, powf | Calculate value raised to a power |
| printf, wprintf | Write data to stdout according to specified format |
| rand | Get pseudorandom number |
| _rotl, _rotr | Shift unsigned int left (_rotl) or right (_rotr) |
| _scalb | Scale argument by power of 2 |
| scanf, wscanf | Read data from stdin according to specified format and write data to specified location |
| sin, sinf, sinh, sinhf | Calculate sine or hyperbolic sine |
| sqrt | Find square root |
| srand | Initialize pseudorandom series |
| _status87, _statusfp | Get floating-point status word |
| strtod | Convert character string to double-precision value |
| tan, tanf, tanh, tanhf | Calculate tangent or hyperbolic tangent |
See Also
Run-Time Routines by Category | Run-Time Routines and .NET Framework Equivalents
