LDEXP(3) Linux Programmer's Manual LDEXP(3)
ldexp, ldexpf, ldexpl - multiply floating-point number by integral power of 2
double ldexp(double x, int exp);
float ldexpf(float x, int exp);
long double ldexpl(long double x, int exp);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
The ldexp() function returns the result of multiplying the floating-point number x by 2
raised to the power exp.
On success, these functions return x * (2^exp).
If exp is zero, then x is returned.
If x is a NaN, a NaN is returned.
If x is positive infinity (negative infinity), positive infinity (negative infinity) is
If the result underflows, a range error occurs, and zero is returned.
If the result overflows, a range error occurs, and the functions return HUGE_VAL,
HUGE_VALF, or HUGE_VALL, respectively, with a sign the same as x.
See math_error(7) for information on how to determine whether an error has occurred when
calling these functions.
The following errors can occur:
Range error, overflow
errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is
Range error, underflow
errno is set to ERANGE. An underflow floating-point exception (FE_UNDERFLOW) is
Multithreading (see pthreads(7))
The ldexp(), ldexpf(), and ldexpl() functions are thread-safe.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
frexp(3), modf(3), scalbln(3)
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