LDEXP(3) Linux Programmer's Manual LDEXP(3) NAME ldexp, ldexpf, ldexpl - multiply floating-point number by integral power of 2 SYNOPSIS #include <math.h> 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)): ldexpf(), ldexpl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L; or cc -std=c99 DESCRIPTION The ldexp() function returns the result of multiplying the floating- point number x by 2 raised to the power exp. RETURN VALUE 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 (nega- tive infinity) is returned. If the result underflows, an 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. ERRORS 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 raised. Range error, underflow errno is set to ERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised. CONFORMING TO C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89. SEE ALSO frexp(3), modf(3), scalbln(3) COLOPHON This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. 2010-09-20 LDEXP(3)
Generated by dwww version 1.11.3 on Wed May 22 06:52:42 CEST 2013.