Type-generic math

 

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Type-generic math

 

The header <tgmath.h> includes the headers <math.h> and <complex.h> and defines several type-generic macros. These macros determines the actual function to call depending on the types of the parameters.

Exponential, power, trigonometric and hyperbolic functions (since C99)

A type-generic macro XXX calls either of:

• real function:

• float variant XXXf
• double variant XXX
• long double variant XXXl

• complex function:

• float variant cXXXf
• double variant cXXX
• long double variant cXXXl

An exception to the above rule is exp (see the table below).

The function to call is determined as follows:

• If any of the parameters is complex, then the complex function is called, otherwise the real function is called.
• If any of the parameters is long double, then the long double variant is called. Otherwise, if any of the parameters is double or integer, then the double variant is called. Otherwise, float variant is called.
• The behavior is undefined if any of the parameters are incompatible with the corresponding argument of the function.

The type-generic macros are as follows:

Type-generic macro	Real function variants			Complex function variants
	float	double	long double	float	double	long double
fabs	fabsf	fabs	fabsl	cabsf	cabs	cabsl
exp	expf	exp	expl	cexpf	cexp	cexpl
log	logf	log	logl	clogf	clog	clogl
pow	powf	pow	powl	cpowf	cpow	cpowl
sqrt	sqrtf	sqrt	sqrtl	csqrtf	csqrt	csqrtl
sin	sinf	sin	sinl	csinf	csin	csinl
cos	cosf	cos	cosl	ccosf	ccos	ccosl
tan	tanf	tan	tanl	ctanf	ctan	ctanl
asin	asinf	asin	asinl	casinf	casin	casinl
acos	acosf	acos	acosl	cacosf	cacos	cacosl
atan	atanf	atan	atanl	catanf	catan	catanl
sinh	sinhf	sinh	sinhl	csinhf	csinh	csinhl
cosh	coshf	cosh	coshl	ccoshf	ccosh	ccoshl
tanh	tanhf	tanh	tanhl	ctanhf	ctanh	ctanhl
asinh	asinhf	asinh	asinhl	casinhf	casinh	casinhl
acosh	acoshf	acosh	acoshl	cacoshf	cacosh	cacoshl
atanh	atanhf	atanh	atanhl	catanhf	catanh	catanhl

Miscellaneous functions (since C99)

A type-generic macro XXX calls either of the variants of a real function:

• float variant XXXf
• double variant XXX
• long double variant XXXl

Note, there's no modf type-generic macro.

The function to call is determined as follows:

• If any of the parameters is long double, then the long double variant is called. Otherwise, if any of the parameters is double, then the double variant is called. Otherwise, float variant is called.
• The behavior is undefined is any of the parameters is incompatible with the corresponding argument of the function.

Type-generic macro	Real function variants
	float	double	long double
atan2	atan2f	atan2	atan2l
cbrt	cbrtf	cbrt	cbrtl
ceil	ceilf	ceil	ceill
copysign	copysignf	copysign	copysignl
erf	erff	erf	erfl
erfc	erfcf	erfc	erfcl
exp2	exp2f	exp2	exp2l
expm1	expm1f	expm1	expm1l
fdim	fdimf	fdim	fdiml
floor	floorf	floor	floorl
fma	fmaf	fma	fmal
fmax	fmaxf	fmax	fmaxl
fmin	fminf	fmin	fminl
fmod	fmodf	fmod	fmodl
frexp	frexpf	frexp	frexpl
hypot	hypotf	hypot	hypotl
ilogb	ilogbf	ilogb	ilogbl
ldexp	ldexpf	ldexp	ldexpl
lgamma	lgammaf	lgamma	lgammal
llrint	llrintf	llrint	llrintl
llround	llroundf	llround	llroundl
log10	log10f	log10	log10l
log1p	log1pf	log1p	log1pl
log2	log2f	log2	log2l
logb	logbf	logb	logbl
lrint	lrintf	lrint	lrintl
lround	lroundf	lround	lroundl
nearbyint	nearbyintf	nearbyint	nearbyintl
nextafter	nextafterf	nextafter	nextafterl
nexttoward	nexttowardf	nexttoward	nexttowardl
remainder	remainderf	remainder	remainderl
remquo	remquof	remquo	remquol
rint	rintf	rint	rintl
round	roundf	round	roundl
scalbln	scalblnf	scalbln	scalblnl
scalbn	scalbnf	scalbn	scalbnl
tgamma	tgammaf	tgamma	tgammal
trunc	truncf	trunc	truncl

Example

Run this code

#include <stdio.h>
#include <tgmath.h>
 
int main(void)
{
                            // macro          -> function call
    int i = 1;
    printf("cos(1) = %f\n",    cos(i) );   // -> cos(i)
 
    float f = 0.5;
    printf("sin(0.5) = %f\n",  sin(f) );   // -> sinf(f)
 
    long double ld = 1;
    printf("acos(1) = %Lf\n",  acos(ld));  // -> acosl(d)
 
    double complex dc = 1 + 0.5*I;
    double complex result = sqrt(dc);      // -> csqrt(dc);
    printf("sqrt(1 + 0.5i) = %f+%fi\n", creal(result), cimag(result));
}

Output:

cos(1) = 0.540302
sin(0.5) = 0.479426
acos(1) = 0.000000
sqrt(1 + 0.5i) = 1.029086+0.242934i