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 + i 0, 1 + i 0 shall be returned.

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

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

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

If iz is +Inf + i 0, +Inf + i 0 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 + i Inf, ±Inf + i NaN 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 + i NaN, +Inf + i NaN shall be returned.

If iz is NaN + i 0, NaN ± i 0 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 + i NaN shall be returned and the invalid floating-point exception may be raised.

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

ERRORS

No errors are defined.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

The MXC special cases for ccos () are derived from those for ccosh(3) by applying the formula ccos ( z) = ccosh ( iz).

FUTURE DIRECTIONS

None.

SEE ALSO

ccosh(3), cacos(3)

XBD <complex.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 (“ISO C99”) standard.

Issue 8

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

End of informative text.