catan(3M)

DESCRIPTION

These functions are available only for IA-64.

catan() returns the complex arctangent of z, in the range of a strip mathematically unbounded along the imaginary axis and in the interval [-Pi/2,+Pi/2] along the real axis. Branch cuts are outside the interval [-1,+1] along the imaginary axis.

catanf() is a float complex version of catan(); it takes a float complex argument and returns a float complex result.

USAGE

To use these functions, compile with the default -Ae option. Make sure your program includes <complex.h>. Link in the math library by specifying -lm on the compiler or linker command line.

RETURN VALUES

catan(conj(z)) = conj(catan(z)) and catan is odd.

catan(+0+i0) returns +0+i0.

catan(+NaN+i0) returns +NaN+i0.

catan(+0+i1) returns +0+iInf and raises the divide-by-zero floating-point exception.

catan(Inf+iy) returns Pi/2+i0, for finite positive-signed y.

catan(NaN+iy) returns NaN+iNaN and optionally raises the invalid floating-point exception, for nonzero finite y.

catan(+x+iInf) returns Pi/2+i0, for finite positive-signed x.

catan(+Inf+iInf) returns Pi/2+i0.

catan(+NaN+iInf) returns +NaN+i0.

catan(x+iNaN) returns NaN+iNaN and optionally raises the invalid floating-point exception, for finite x.

catan(Inf+iNaN) returns Pi/2+-i0 (where the sign of the imaginary part of the result is unspecified).

catan(NaN+iNaN) returns NaN+iNaN.

ERRORS

No errors are defined.

SEE ALSO

atan(3M), ctan(3M), complex(5).

STANDARDS CONFORMANCE

catan(), catanf(): ISO/IEC C99 (including Annex G, IEC 60559-compatible complex arithmetic)