# catanf, catan, catanl

< c‎ | numeric‎ | complex

C
 Language Headers Type support Program utilities Variadic function support Error handling Dynamic memory management Date and time utilities Strings library Algorithms Numerics Input/output support Localization support Atomic operations (C11) Thread support (C11) Technical Specifications

Complex number arithmetic
Types and the imaginary constant
Manipulation
Power and exponential functions
Trigonometric functions
 cacos casin catan
Hyperbolic functions

 Defined in header  float complex       catanf( float complex z ); (1) (since C99) double complex      catan( double complex z ); (2) (since C99) long double complex catanl( long double complex z ); (3) (since C99) Defined in header  #define atan( z ) (4) (since C99)
1-3) Computes the complex arc tangent of z with branch cuts outside the interval [−i,+i] along the imaginary axis.
4) Type-generic macro: If z has type long double complex, catanl is called. if z has type double complex, catan is called, if z has type float complex, catanf is called. If z is real or integer, then the macro invokes the corresponding real function (atanf, atan, atanl). If z is imaginary, then the macro invokes the corresponding real version of the function atanh, implementing the formula atan(iy) = i atanh(y), and the return type of the macro is imaginary.

## Contents

### Parameters

 z - complex argument

### Return value

If no errors occur, complex arc tangent of z is returned, in the range of a strip unbounded along the imaginary axis and in the interval [−π/2; +π/2] along the real axis.

Errors and special cases are handled as if the operation is implemented by -I * catanh(I*z).