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The latest version of this topic can be found at _CIatan2.

Calculates the arctangent of x / y where x and y are values on the top of the stack.

void __cdecl _CIatan2();  

This version of the atan2 function has a specialized calling convention that the compiler understands. It speeds up the execution because it prevents copies from being generated and helps with register allocation.

The resulting value is pushed onto the top of the stack.

Platform: x86

Alphabetical Function Reference
atan, atanf, atanl, atan2, atan2f, atan2l