TRUNC(3) Linux Programmer's Manual TRUNC(3)
trunc, truncf, truncl - round to integer, toward zero
double trunc(double x);
float truncf(float x);
long double truncl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
trunc(), truncf(), truncl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
These functions round x to the nearest integer not larger in absolute value.
These functions return the rounded integer value.
If x is integral, infinite, or NaN, x itself is returned.
No errors occur.
These functions first appeared in glibc in version 2.1.
Multithreading (see pthreads(7))
The trunc(), truncf(), and truncl() functions are thread-safe.
The integral value returned by these functions may be too large to store in an integer
type (int, long, etc.). To avoid an overflow, which will produce undefined results, an
application should perform a range check on the returned value before assigning it to an
ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3)
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