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c99 [ flag... ] file... -lm [ library... ] #include <math.h> double hypot(double x, double y);
float hypotf(float x, float y);
long double hypotl(long double x, long double y);
These functions compute the length of the square root of x^2 + y^2 without undue overflow or underflow.
Upon successful completion, these functions return the length of the hypotenuse of a right angled triangle with sides of length x^2 and y^2.
If the correct value would cause overflow, a range error occurs and hypot(), hypotf(), and hypotl() return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.
If x or y is \(+-Inf, +Inf is returned even if one of x or y is NaN.
If x or y is NaN and the other is not \(+-Inf, a NaN is returned.
These functions will fail if:
Range Error
The result overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception is raised.
hypot(x,y), hypot(y,x), and hypot(x, -y) are equivalent.
hypot(x, \(+-0) is equivalent to fabs(x).
These functions takes precautions against underflow and overflow during intermediate steps of the computation.
An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Interface Stability | Standard |
| MT-Level | MT-Safe |
fabs(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), math.h(3HEAD), sqrt(3M), attributes(5), standards(5)