This chapter contains information about functions for performing mathematical computations, such as trigonometric functions. Most of these functions have prototypes declared in the header file math.h. The complex-valued functions are defined in complex.h.
All mathematical functions which take a floating-point argument
have three variants, one each for
long double arguments. The
double versions are mostly
defined in ISO C89. The
versions are from the numeric extensions to C included in ISO C99.
Which of the three versions of a function should be used depends on the
situation. For most calculations, the
float functions are the
fastest. On the other hand, the
long double functions have the
double is somewhere in between. It is
usually wise to pick the narrowest type that can accommodate your data.
Not all machines have a distinct
long double type; it may be the