NAME

ccos, ccosf, ccosl — complex cosine functions

SYNOPSIS

#include <complex.h>

double complex ccos(double complex z);
float complex ccosf(float complex z);
long double complex ccosl(long double complex z);


DESCRIPTION

^[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.

These functions shall compute the complex cosine of z.

RETURN VALUE

These functions shall return the complex cosine value.

^[MXC] ccos(conj(iz)), ccosf(conjf(iz)), and ccosl(conjl(iz)) shall return exactly the same value as conj(ccos(iz)), conjf(ccosf(iz)), and conjl(ccosl(iz)), respectively, and ccos(-iz), ccosf(-iz), and ccosl(-iz) shall return exactly the same value as ccos(iz), ccosf(iz), and ccosl(iz), respectively, including for the special values of iz below.

If iz is +0 + i0, 1 + i0 shall be returned.

If iz is +0 + iInf, NaN ± i0 shall be returned and the invalid floating-point exception shall be raised; the sign of the imaginary part of the result is unspecified.

If iz is +0 + iNaN, NaN ± i0 shall be returned; the sign of the imaginary part of the result is unspecified.

If iz is x + iInf where x is non-zero and finite, NaN + iNaN shall be returned and the invalid floating-point exception shall be raised.

If iz is x + iNaN where x is non-zero and finite, NaN + iNaN shall be returned and the invalid floating-point exception may be raised.

If iz is +Inf + i0, +Inf + i0 shall be returned.

If iz is +Inf + iy where y is non-zero and finite, +Inf (cos(y) + isin(y)) shall be returned.

If iz is +Inf + iInf, ±Inf + iNaN shall be returned and the invalid floating-point exception shall be raised; the sign of the real part of the result is unspecified.

If iz is +Inf + iNaN, +Inf + iNaN shall be returned.

If iz is NaN + i0, NaN ± i0 shall be returned; the sign of the imaginary part of the result is unspecified.

If iz is NaN + iy where y is any non-zero number, NaN + iNaN shall be returned and the invalid floating-point exception may be raised.

If iz is NaN + iNaN, NaN + iNaN shall be returned.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

The MXC special cases for ccos() are derived from those for ccosh() by applying the formula ccos(z) = ccosh(iz).

FUTURE DIRECTIONS

None.

SEE ALSO

ccosh, cacos

XBD <complex.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

Issue 8

Austin Group Defect 1302 is applied, aligning these functions with the ISO/IEC 9899:2018 standard.