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Defined in header <math.h> | ||
float acosf(float arg); | (1) | (since C99) |
double acos(double arg); | (2) | |
longdouble acosl(longdouble arg); | (3) | (since C99) |
_Decimal32 acosd32( _Decimal32 arg); | (4) | (since C23) |
_Decimal64 acosd64( _Decimal64 arg); | (5) | (since C23) |
_Decimal128 acosd128( _Decimal128 arg); | (6) | (since C23) |
Defined in header <tgmath.h> | ||
#define acos( arg ) | (7) | (since C99) |
acosl) is called. Otherwise, if the argument has integer type or the typedouble,(2) (acos) is called. Otherwise,(1) (acosf) is called. If the argument is complex, then the macro invokes the corresponding complex function (cacosf,cacos,cacosl).The functions(4-6) are declared if and only if the implementation predefines | (since C23) |
Contents |
| arg | - | floating-point value |
If no errors occur, the arc cosine ofarg (arccos(arg)) in the range[0 ; π], 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.
Errors are reported as specified inmath_errhandling.
Domain error occurs ifarg is outside the range[-1.0; 1.0].
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
+0 is returned;#include <errno.h>#include <fenv.h>#include <math.h>#include <stdio.h>#include <string.h> #ifndef __GNUC__#pragma STDC FENV_ACCESS ON#endif int main(void){printf("acos(-1) = %f\n", acos(-1));printf("acos(0.0) = %f 2*acos(0.0) = %f\n", acos(0),2* acos(0));printf("acos(0.5) = %f 3*acos(0.5) = %f\n", acos(0.5),3* acos(0.5));printf("acos(1) = %f\n", acos(1)); // error handlingerrno=0;feclearexcept(FE_ALL_EXCEPT);printf("acos(1.1) = %f\n", acos(1.1));if(errno==EDOM)perror(" errno == EDOM");if(fetestexcept(FE_INVALID))puts(" FE_INVALID raised");}
Possible output:
acos(-1) = 3.141593acos(0.0) = 1.570796 2*acos(0.0) = 3.141593acos(0.5) = 1.047198 3*acos(0.5) = 3.141593acos(1) = 0.000000acos(1.1) = nan errno == EDOM: Numerical argument out of domain FE_INVALID raised
(C99)(C99) | computes arc sine (\({\small\arcsin{x} }\)arcsin(x)) (function)[edit] |
(C99)(C99) | computes arc tangent (\({\small\arctan{x} }\)arctan(x)) (function)[edit] |
(C99)(C99) | computes arc tangent, using signs to determine quadrants (function)[edit] |
(C99)(C99) | computes cosine (\({\small\cos{x} }\)cos(x)) (function)[edit] |
(C99)(C99)(C99) | computes the complex arc cosine (function)[edit] |
C++ documentation foracos | |
