c99 [ flag... ] file... -lm [ library... ] #include <math.h>
long lrint(double x);
long lrintf(float x);
These functions round their argument to the nearest integer value, rounding according to the current rounding direction.
Upon successful completion, these functions return the rounded integer value.
If x is NaN, a domain error occurs and an unspecified value is returned.
If x is +Inf, a domain error occurs and an unspecified value is returned.
If x is -Inf, a domain error occurs and an unspecified value is returned.
If the correct value is positive and too large to represent as a long, a domain error occurs and an unspecified value is returned.
If the correct value is negative and too large to represent as a long, a domain error occurs and an unspecified value is returned.
These functions will fail if:
Domain Error The x argument is NaN or ±Inf, or the correct value is not representable as an integer.
If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised.
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 |
feclearexcept(3M), fetestexcept(3M), llrint(3M), math.h(3HEAD), attributes(5), standards(5)