ARM Compiler toolchain v4.1 for µVision Using the Compiler

Compiler Coding Practices
5.75 Additional library functions in C99
C99 supports additional macros, types, and functions in the standard header that are
not found in the corresponding C90 standard header.
New macros found in C99 that are not found in C90 include:
INFINITY // positive infinity
NAN // IEEE not-a-number
New generic function macros found in C99 that are not found in C90 include:
#define isinf(x) // non-zero only if x is positive or negative infinity
#define isnan(x) // non-zero only if x is NaN
#define isless(x, y) // 1 only if x < y and x and y are not NaN, and 0 otherwise
#define isunordered(x, y) // 1 only if either x or y is NaN, and 0 otherwise
New mathematical functions found in C99 that are not found in C90 include:
double acosh(double x); // hyperbolic arccosine of x
double asinh(double x); // hyperbolic arcsine of x
double atanh(double x); // hyperbolic arctangent of x
double erf(double x); // returns the error function of x
double round(double x); // returns x rounded to the nearest integer
double tgamma(double x); // returns the gamma function of x
C99 supports the new mathematical functions for all real floating-point types.
Single precision versions of all existing functions are also supported.
5.75.1 See also
Concepts
• New library features of C99 on page 5-79.
Other information
• Institute of Electrical and Electronics Engineers, http://www.ieee.org
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