File dp_complex.h¶

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The complex-math surface, routed so it survives Windows. More...

#include <complex.h>

Detailed Description¶

Include this instead of <complex.h>. On Linux and macOS it IS <complex.h> and nothing changes; on Windows it supplies the same names without touching the platform header.

Why the indirection¶

MSVC has no _Complex keyword at all. Its <complex.h> is built around _Fcomplex/_Dcomplex STRUCTS, with arithmetic in function form (_FCmulcc) so crealf there is declared as taking an _Fcomplex, while doppler passes a native float _Complex. The two cannot meet.

clang-cl does implement _Complex while targeting the MSVC ABI, so the language half is free. The library half is not: MSVC's <complex.h> declares every name struct-shaped. So this header supplies the surface from clang builtins plus REAL-valued libm, under doppler-owned names, and points the C99 names at them by macro.

It does include MSVC's <complex.h> FIRST, and only so that nothing else includes it later. numpy's npy_common.h includes it on every MSVC build, so every Python extension pulled it in AFTER this header: its cabsf(_Fcomplex) then collided with the definition here, and its I a _Fcomplex struct replaced this header's, so x * I in any inline header function stopped compiling (doppler#1457, the first Windows make pyext). Included first, its declarations are made before any name below is a macro, and its include guard makes every later include a no-op.

Measured on clang 22 targeting x86_64-pc-windows-msvc with doppler's own flags (-O3 -march=x86-64-v2 -ffast-math -fno-finite-math-only): a complex DSP kernel compiled through this header leaves exactly these undefined symbols. All five are plain-float UCRT exports. No _Fcomplex crosses the ABI, and __mulsc3/__divsc3 inline away under -ffast-math, so there is no compiler-rt dependency either. That is why cabsf/cargf/cexpf are routed through hypotf/atan2f/expf+cosf/sinf rather than being left to lower to the CRT's complex-typed entry points.

Note:

On Linux and macOS this is a pure passthrough the same <complex.h> symbols, unchanged so numerics cannot drift between platforms by way of this header.

The documentation for this class was generated from the following file native/inc/doppler/dp_complex.h