cbrt, cbrtf, cbrtl

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Error handling
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Concurrency support(C11)
Technical Specifications
Symbol index

[edit]

Numerics

Common mathematical functions
Floating-point environment(C99)
Pseudo-random number generation
Complex number arithmetic(C99)
Type-generic math(C99)
Bit manipulation(C23)
Checked integer arithmetic(C23)

[edit]

Common mathematical functions

Functions

Basic operations

abslabsllabsimaxabs (C99)(C99)
fabs
divldivlldivimaxdiv (C99)(C99)

fmod
remainder (C99)
remquo (C99)
fma (C99)
fdim (C99)
nannanfnanlnandN (C99)(C99)(C99)(C23)

Maximum/minimum operations

fmax (C99)
fmin (C99)
fmaximum (C23)
fminimum (C23)
fmaximum_mag (C23)

fmaximum_num (C23)
fminimum_mag (C23)
fminimum_num (C23)
fmaximum_mag_num (C23)
fminimum_mag_num (C23)

Exponential functions

exp
exp10 (C23)
exp2 (C99)
expm1 (C99)
exp10m1 (C23)
exp2m1 (C23)

log
log10
log2 (C99)
log1plogp1 (C99)(C23)
log10p1 (C23)
log2p1 (C23)

Power functions

sqrt
cbrt (C99)
rootn (C23)
rsqrt (C23)

hypot (C99)
compound (C23)
pow
pown (C23)
powr (C23)

Trigonometric and hyperbolic functions

sin
cos
tan
asin
acos
atan
atan2
sinpi (C23)
cospi (C23)
tanpi (C23)

asinpi (C23)
acospi (C23)
atanpi (C23)
atan2pi (C23)
sinh
cosh
tanh
asinh (C99)
acosh (C99)
atanh (C99)

Nearest integer floating-point

ceil
floor
roundlroundllround (C99)(C99)(C99)
roundeven (C23)
trunc (C99)

nearbyint (C99)
rintlrintllrint (C99)(C99)(C99)
fromfpfromfpxufromfpufromfpx (C23)(C23)(C23)(C23)

Floating-point manipulation

ldexp
frexp
scalbnscalbln (C99)(C99)
ilogbllogb (C99)(C23)
logb (C99)

modf
nextafternexttoward (C99)(C99)
nextupnextdown (C23)(C23)
copysign (C99)
canonicalize (C23)

Narrowing operations

fadd (C23)
fsub (C23)
fmul (C23)

fdiv (C23)
ffma (C23)
fsqrt (C23)

Quantum and quantum exponent

quantizedN (C23)
quantumdN (C23)

samequantumdN (C23)
llquantexpdN (C23)

Decimal re-encoding functions

encodedecdN (C23)
decodedecdN (C23)

encodebindN (C23)
decodebindN (C23)

Total order and payload functions

totalorder (C23)
getpayload (C23)

setpayload (C23)
setpayloadsig (C23)

Classification

fpclassify (C99)
iscanonical (C23)
isfinite (C99)
isinf (C99)
isnan (C99)
isnormal (C99)
signbit (C99)
issubnormal (C23)
iszero (C23)

isgreater (C99)
isgreaterequal (C99)
isless (C99)
islessequal (C99)
islessgreater (C99)
isunordered (C99)
issignaling (C23)
iseqsig (C23)

Error and gamma functions

erf (C99)
erfc (C99)

lgamma (C99)
tgamma (C99)

Types

div_tldiv_tlldiv_timaxdiv_t

(C99)(C99)

float_tdouble_t (C99)(C99)
_Decimal32_t_Decimal64_t (C23)(C23)

Macro constants

Special floating-point values

HUGE_VALHUGE_VALFHUGE_VALLHUGE_VALDN

(C99)(C99)(C23)

INFINITYDEC_INFINITY (C99)(C23)
NANDEC_NAN (C99)(C23)

Arguments and return values

FP_ILOGB0FP_ILOGBNAN (C99)(C99)
FP_NORMALFP_SUBNORMALFP_ZEROFP_INFINITEFP_NAN (C99)(C99)(C99)(C99)(C99)

FP_LLOGB0FP_LLOGBNAN (C23)(C23)
FP_INT_UPWARDFP_INT_DOWNWARDFP_INT_TOWARDZEROFP_INT_TONEARESTFROMZEROFP_INT_TONEAREST (C23)(C23)(C23)(C23)(C23)

Error handling

MATH_ERRNOMATH_ERRNOEXCEPT

(C99)(C99)

math_errhandling (C99)

Fast operation indicators

FP_FAST_FMAFFP_FAST_FMA (C99)(C99)
FP_FAST_FADDFP_FAST_FADDLFP_FAST_DADDLFP_FAST_DMADDDN (C23)(C23)(C23)(C23)
FP_FAST_FMULFP_FAST_FMULLFP_FAST_DMULLFP_FAST_DMMULDN (C23)(C23)(C23)(C23)
FP_FAST_FFMAFP_FAST_FFMALFP_FAST_DFMALFP_FAST_DMFMADN (C23)(C23)(C23)(C23)

FP_FAST_FMALFP_FAST_FMADN (C99)(C23)
FP_FAST_FSUBFP_FAST_FSUBLFP_FAST_DSUBLFP_FAST_DMSUBDN (C23)(C23)(C23)(C23)
FP_FAST_FDIVFP_FAST_FDIVLFP_FAST_DDIVLFP_FAST_DMDIVDN (C23)(C23)(C23)(C23)
FP_FAST_FSQRTFP_FAST_FSQRTLFP_FAST_DSQRTLFP_FAST_DMSQRTDN (C23)(C23)(C23)(C23)

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Defined in header`<math.h>`
float cbrtf(float arg);	(1)	(since C99)
double cbrt(double arg);	(2)	(since C99)
longdouble cbrtl(longdouble arg);	(3)	(since C99)
Defined in header`<tgmath.h>`
#define cbrt( arg )	(4)	(since C99)

1-3) Computes the cube root ofarg.

4) Type-generic macro: Ifarg has typelongdouble,cbrtl is called. Otherwise, ifarg has integer type or the typedouble,cbrt is called. Otherwise,cbrtf is called.

[edit]Parameters

arg

floating-point value

[edit]Return value

If no errors occur, the cube root ofarg (\(\small{\sqrt[3]{arg} }\)3√arg), is returned.

If a range error occurs due to underflow, the correct result (after rounding) is returned.

[edit]Error handling

Errors are reported as specified inmath_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

if the argument is ±0 or ±∞, it is returned, unchanged
if the argument is NaN, NaN is returned.

[edit]Notes

cbrt(arg) is not equivalent topow(arg,1.0/3) because the rational number\(\small{\frac1{3} }\)

is typically not equal to1.0/3 andstd::pow cannot raise a negative base to a fractional exponent. Moreover,cbrt(arg) usually gives more accurate results thanpow(arg,1.0/3) (see example).

[edit]Example

Run this code

#include <float.h>#include <math.h>#include <stdio.h> int main(void){printf("Normal use:\n""cbrt(729)      = %f\n", cbrt(729));printf("cbrt(-0.125)   = %f\n", cbrt(-0.125));printf("Special values:\n""cbrt(-0)       = %f\n", cbrt(-0.0));printf("cbrt(+inf)     = %f\n", cbrt(INFINITY));printf("Accuracy:\n""cbrt(343)      = %.*f\n", DBL_DECIMAL_DIG, cbrt(343));printf("pow(343,1.0/3) = %.*f\n", DBL_DECIMAL_DIG,pow(343,1.0/3));}

Possible output:

Normal use:cbrt(729)      = 9.000000cbrt(-0.125)   = -0.500000Special values:cbrt(-0)       = -0.000000cbrt(+inf)     = infAccuracy:cbrt(343)      = 7.00000000000000000pow(343,1.0/3) = 6.99999999999999911

[edit]References

C23 standard (ISO/IEC 9899:2024):

7.12.7.1 The cbrt functions (p: TBD)

7.25 Type-generic math <tgmath.h> (p: TBD)

F.10.4.1 The cbrt functions (p: TBD)

C17 standard (ISO/IEC 9899:2018):

7.12.7.1 The cbrt functions (p: 180-181)

7.25 Type-generic math <tgmath.h> (p: 272-273)

F.10.4.1 The cbrt functions (p: 381-)

C11 standard (ISO/IEC 9899:2011):

7.12.7.1 The cbrt functions (p: 247)

7.25 Type-generic math <tgmath.h> (p: 373-375)

F.10.4.1 The cbrt functions (p: 524)

C99 standard (ISO/IEC 9899:1999):

7.12.7.1 The cbrt functions (p: 228)

7.22 Type-generic math <tgmath.h> (p: 335-337)

F.9.4.1 The cbrt functions (p: 460)

[edit]See also

powpowfpowl (C99)(C99)	computes a number raised to the given power (\(\small{x^y}\)x^y) (function)[edit]
sqrtsqrtfsqrtl (C99)(C99)	computes square root (\(\small{\sqrt{x} }\)√x) (function)[edit]
hypothypotfhypotl (C99)(C99)(C99)	computes square root of the sum of the squares of two given numbers (\(\scriptsize{\sqrt{x^2+y^2} }\)√x2 +y2 ) (function)[edit]
C++ documentation forcbrt