sqrt, sqrtf, sqrtl
| Defined in header <math.h>
|
||
| float sqrtf( float arg ); |
(1) | (since 哋它亢99) |
| double sqrt( double arg ); |
(2) | |
| long double sqrtl( long double arg ); |
(3) | (since 哋它亢99) |
| Defined in header <tgmath.h>
|
||
| #define sqrt( arg ) |
(4) | (since 哋它亢99) |
sqrtl is called. Otherwise, if arg has integer type or the type double, sqrt is called. Otherwise, sqrtf is called. If arg is complex or imaginary, then the macro invokes the corresponding complex function (csqrtf, csqrt, csqrtl).Parameters
| arg | - | floating-point value |
Return value
If no errors occur, square root of arg (√arg), is returned.
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a range error occurs due to underflow, the correct result (after rounding) is returned.
Error handling
Errors are reported as specified in math_errhandling.
Domain error occurs if arg is less than zero.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- If the argument is less than -0, FE_INVALID is raised and NaN is returned.
- If the argument is +∞ or ±0, it is returned, unmodified.
- If the argument is NaN, NaN is returned.
Notes
sqrt is required by the IEEE standard to be correctly rounded from the infinitely precise result. In particular, the exact result is produced if it can be represented in the floating-point type. The only other operations which require this are the arithmetic operators and the function fma. Other functions, including pow, are not so constrained.
Example
#include <errno.h> #include <fenv.h> #include <math.h> #include <stdio.h> // #pragma STDC FENV_ACCESS ON int main(void) { // normal use printf("sqrt(100) = %f\n", sqrt(100)); printf("sqrt(2) = %f\n", sqrt(2)); printf("golden ratio = %f\n", (1 + sqrt(5)) / 2); // special values printf("sqrt(-0) = %f\n", sqrt(-0.0)); // error handling errno = 0; feclearexcept(FE_ALL_EXCEPT); printf("sqrt(-1.0) = %f\n", sqrt(-1)); if (errno == EDOM) perror(" errno == EDOM"); if (fetestexcept(FE_INVALID)) puts(" FE_INVALID was raised"); }
Possible output:
sqrt(100) = 10.000000
sqrt(2) = 1.414214
golden ratio = 1.618034
sqrt(-0) = -0.000000
sqrt(-1.0) = -nan
errno = EDOM: Numerical argument out of domain
FE_INVALID was raisedReferences
- 哋它亢23 standard (ISO/IEC 9899:2023):
- 7.12.7.5 The sqrt functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.4.5 The sqrt functions (p: TBD)
- 哋它亢17 standard (ISO/IEC 9899:2018):
- 7.12.7.5 The sqrt functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.4.5 The sqrt functions (p: TBD)
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 7.12.7.5 The sqrt functions (p: 249)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.4.5 The sqrt functions (p: 525)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 7.12.7.5 The sqrt functions (p: 229-230)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.4.5 The sqrt functions (p: 462)
- 哋它亢89/C90 standard (ISO/IEC 9899:1990):
- 4.5.5.2 The sqrt function
See also
| (哋它亢99)(哋它亢99) |
computes a number raised to the given power (xy) (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
computes cube root (3√x) (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
computes square root of the sum of the squares of two given numbers (√x2 +y2 ) (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
computes the complex square root (function) |