Names specified here
Name	Description			Source
`erf()`	Compute error function		(·)	`<math.h>`	C99	C11
`erf()`	Compute error function	M	(·)	`<tgmath.h>`	C99	C11
`erfc()`	Compute complementary error function	M	(·)	`<tgmath.h>`	C99	C11
`erfc()`	Compute complementary error function		(·)	`<math.h>`	C99	C11
`erfcf()`	Compute complementary error function		(·)	`<math.h>`	C99	C11
`erfcl()`	Compute complementary error function		(·)	`<math.h>`	C99	C11
`erff()`	Compute error function		(·)	`<math.h>`	C99	C11
`erfl()`	Compute error function		(·)	`<math.h>`	C99	C11
`fdim()`	Compute positive difference		(·)	`<math.h>`	C99	C11
`fdim()`	Compute positive difference	M	(·)	`<tgmath.h>`	C99	C11
`fdimf()`	Compute positive difference		(·)	`<math.h>`	C99	C11
`fdiml()`	Compute positive difference		(·)	`<math.h>`	C99	C11
`fmax()`	Select maximum	M	(·)	`<tgmath.h>`	C99	C11
`fmax()`	Select maximum		(·)	`<math.h>`	C99	C11
`fmaxf()`	Select maximum		(·)	`<math.h>`	C99	C11
`fmaxl()`	Select maximum		(·)	`<math.h>`	C99	C11
`fmin()`	Select minimum	M	(·)	`<tgmath.h>`	C99	C11
`fmin()`	Select minimum		(·)	`<math.h>`	C99	C11
`fminf()`	Select minimum		(·)	`<math.h>`	C99	C11
`fminl()`	Select minimum		(·)	`<math.h>`	C99	C11
`lgamma()`	Compute natural logarithm of gamma		(·)	`<math.h>`	C99	C11
`lgamma()`	Compute natural logarithm of gamma	M	(·)	`<tgmath.h>`	C99	C11
`lgammaf()`	Compute natural logarithm of gamma		(·)	`<math.h>`	C99	C11
`lgammal()`	Compute natural logarithm of gamma		(·)	`<math.h>`	C99	C11
`tgamma()`	Compute gamma	M	(·)	`<tgmath.h>`	C99	C11
`tgamma()`	Compute gamma		(·)	`<math.h>`	C99	C11
`tgammaf()`	Compute gamma		(·)	`<math.h>`	C99	C11
`tgammal()`	Compute gamma		(·)	`<math.h>`	C99	C11

Minima and maxima

#include <math.h>
float fminf(float x, float y);
double fmin(double x, double y);
long double fminl(long double x, long double y);

#include <tgmath.h>
real-floating-type fmin(real-floating-type x, real-floating-type y);

The fmin functions return the lower of their two arguments x and y.

#include <math.h>
float fmaxf(float x, float y);
double fmax(double x, double y);
long double fmaxl(long double x, long double y);

#include <tgmath.h>
real-floating-type fmax(real-floating-type x, real-floating-type y);

The fmax functions return the higher of their two arguments x and y.

#include <math.h>
float fdimf(float x, float y);
double fdim(double x, double y);
long double fdiml(long double x, long double y);

#include <tgmath.h>
real-floating-type fdim(real-floating-type x, real-floating-type y);

The fdim functions return x-y if positive, or zero otherwise.

Gauss error function

The normal distribution function of x is e^−x². The error function is the integral of the normal distribution.

#include <math.h>
float erff(float x);
double erf(double x);
long double erfl(long double x);
float erfcf(float x);
double erfc(double x);
long double erfcl(long double x);

#include <tgmath.h>
real-floating-type erf(real-floating-type x);
real-floating-type erfc(real-floating-type x);

Functions with names matching ^c(erf|erfc)(|f|l)$ might be added to <complex.h>.

The erf functions compute and return the error function of x, integrating over the range zero to x. The erfc functions compute and return the complementary error function of x, integrating over the range x to +∞.

Gamma function

The gamma function is the continuous version of the factorial function, such that Γ(n+1) = n! for n∈ℕ. Six C functions are provided by <math.h> for computing the gamma function.

#include <math.h>
float tgammaf(float x);
double tgamma(double x);
long double tgammal(long double x);

#include <tgmath.h>
real-floating-type tgamma(real-floating-type x);

Functions with names matching ^ctgamma(|f|l)$ might be added to <complex.h>.

The tgamma functions compute and return the gamma function of x, Γ(x).

#include <math.h>
float lgammaf(float x);
double lgamma(double x);
long double lgammal(long double x);

#include <tgmath.h>
real-floating-type lgamma(real-floating-type x);

Functions with names matching ^clgamma(|f|l)$ might be added to <complex.h>.

The lgamma functions compute and return natural logarithm of the gamma function of x, ln |Γ(x)|.