acos(), acosf() arc cosine function	Function
	SYNOPSIS DESCRIPTION PARAMETERS RETURN VALUES CONFORMANCE MULTITHREAD SAFETY LEVEL PORTING ISSUES AVAILABILITY SEE ALSO

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SYNOPSIS

#include <math.h>

double acos(double x)

float acosf(float x)

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DESCRIPTION

The acos() and acosf() functions compute the principal value of the arc cosine of x in the range [0, Pi].

An application wishing to check for error situations should set errno to 0 before calling acos(). If errno is non-zero on return, or the value NaN is returned, an error has occurred.

The acosf() function is a single-precision version of acos().

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PARAMETERS

x 

Value between -1 and +1 whose arc cosine is to be calculated.

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RETURN VALUES

If |x|>1, acos(x) and acosf(x) return the following values based on the current math mode:

• In IEEE mode, NaN is returned.

• In POSIX mode, 0.0 is returned and errno is set to EDOM.

• In SVID or XOPEN mode, matherr() is called.

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CONFORMANCE

acos(): ANSI/ISO 9899-1990

acosf(): PTC MKS Toolkit UNIX APIs extension

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MULTITHREAD SAFETY LEVEL

MT-Safe.

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PORTING ISSUES

None.

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AVAILABILITY

PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition

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SEE ALSO

Functions:

asin(), atan(), atan2(), cos(), cosh(), math(), matherr(), sin(), sinh(), tan(), tanh()

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PTC MKS Toolkit 10.4 Documentation Build 39.