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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |ATTRIBUTES |STANDARDS |HISTORY |BUGS |SEE ALSO |COLOPHON | |
pow(3) Library Functions Manualpow(3)pow, powf, powl - power functions
Math library (libm,-lm)
#include <math.h>double pow(doublex, doubley);float powf(floatx, floaty);long double powl(long doublex, long doubley); Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):powf(),powl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions return the value ofx raised to the power ofy.
On success, these functions return the value ofx to the power ofy. If the result overflows, a range error occurs, and the functions returnHUGE_VAL,HUGE_VALF, orHUGE_VALL, respectively, with the mathematically correct sign. If result underflows, and is not representable, a range error occurs, and 0.0 with the appropriate sign is returned. Ifx is +0 or -0, andy is an odd integer less than 0, a pole error occurs andHUGE_VAL,HUGE_VALF, orHUGE_VALL, is returned, with the same sign asx. Ifx is +0 or -0, andy is less than 0 and not an odd integer, a pole error occurs and +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, is returned. Ifx is +0 (-0), andy is an odd integer greater than 0, the result is +0 (-0). Ifx is 0, andy greater than 0 and not an odd integer, the result is +0. Ifx is -1, andy is positive infinity or negative infinity, the result is 1.0. Ifx is +1, the result is 1.0 (even ify is a NaN). Ify is 0, the result is 1.0 (even ifx is a NaN). Ifx is a finite value less than 0, andy is a finite noninteger, a domain error occurs, and a NaN is returned. If the absolute value ofx is less than 1, andy is negative infinity, the result is positive infinity. If the absolute value ofx is greater than 1, andy is negative infinity, the result is +0. If the absolute value ofx is less than 1, andy is positive infinity, the result is +0. If the absolute value ofx is greater than 1, andy is positive infinity, the result is positive infinity. Ifx is negative infinity, andy is an odd integer less than 0, the result is -0. Ifx is negative infinity, andy less than 0 and not an odd integer, the result is +0. Ifx is negative infinity, andy is an odd integer greater than 0, the result is negative infinity. Ifx is negative infinity, andy greater than 0 and not an odd integer, the result is positive infinity. Ifx is positive infinity, andy less than 0, the result is +0. Ifx is positive infinity, andy greater than 0, the result is positive infinity. Except as specified above, ifx ory is a NaN, the result is a NaN.
Seemath_error(7) for information on how to determine whether an error has occurred when calling these functions. The following errors can occur: Domain error:x is negative, andy is a finite nonintegererrno is set toEDOM. An invalid floating-point exception (FE_INVALID) is raised. Pole error:x is zero, andy is negativeerrno is set toERANGE(but see BUGS). A divide-by-zero floating-point exception (FE_DIVBYZERO) is raised. Range error: the result overflowserrno is set toERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised. Range error: the result underflowserrno is set toERANGE. An underflow floating-point exception (FE_UNDERFLOW) is raised.
For an explanation of the terms used in this section, seeattributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface│Attribute│Value│ ├──────────────────────────────────────┼───────────────┼─────────┤ │pow(),powf(),powl() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
C99, POSIX.1-2001. The variant returningdouble also conforms to SVr4, 4.3BSD, C89.
Historical bugs (now fixed) Before glibc 2.28, on some architectures (e.g., x86-64)pow() may be more than 10,000 times slower for some inputs than for other nearby inputs. This affects onlypow(), and notpowf() norpowl(). This problem was fixed in glibc 2.28. A number of bugs in the glibc implementation ofpow() were fixed in glibc 2.16. In glibc 2.9 and earlier, when a pole error occurs,errno is set toEDOMinstead of the POSIX-mandatedERANGE. Since glibc 2.10, glibc does the right thing. In glibc 2.3.2 and earlier, when an overflow or underflow error occurs, glibc'spow() generates a bogus invalid floating-point exception (FE_INVALID) in addition to the overflow or underflow exception.
cbrt(3),cpow(3),sqrt(3)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-05-17pow(3)Pages that refer to this page:cbrt(3), cpow(3), pow10(3)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |