FMA(3) | Library Functions Manual | FMA(3)

# NAME

`fma`, `fmaf`, `fmal` — floating multiply-add

# SYNOPSIS

Math Library (libm, -lm)
`#include <math.h>`

double
`fma`(double x, double y, double z);

float
`fmaf`(float x, float y, float z);

long double
`fmal`(long double x, long double y, long double z);

# DESCRIPTION

The `fma`(), `fmaf`() and `fmal`() functions compute (x * y) + z, rounded as one ternary operation. The result is rounded according to the current rounding mode.

# RETURN VALUES

The `fma`(), `fmaf`() and `fmal`() functions return (x * y) + z, rounded as one ternary operation.

# SEE ALSO

fegetround(3), remainder(3)

# STANDARDS

The `fma`(), `fmaf`() and `fmal`() functions conform to ISO/IEC 9899:1999 (“ISO C99”).

June 7, 2025 | Debian