#include <tgmath.h>

The <tgmath.h> header includes the headers <math.h> and <complex.h> and defines several type-generic macros.

Of the functions contained within the <math.h> and <complex.h> headers without an f (float) or l (long double) suffix, several have one or more parameters whose corresponding real type is double. For each such function except modf(3M), there is a corresponding type-generic macro. The parameters whose corresponding real type is double in the function synopsis are generic parameters. Use of the macro invokes a function whose corresponding real type and type domain are determined by the arguments for the generic parameters.

Use of the macro invokes a function whose generic parameters have the corresponding real type determined as follows:

For each unsuffixed function in the <math.h> header for which there is a function in the <complex.h> header with the same name except for a c prefix, the corresponding type-generic macro (for both functions) has the same name as the function in the <math.h> header. The corresponding type-generic macro for fabs() and cabs() is fabs().

If at least one argument for a generic parameter is complex, then use of the macro invokes a complex function; otherwise, use of the macro invokes a real function.

For each unsuffixed function in the <math.h> header without a c-prefixed counterpart in the <complex.h> header, the corresponding type-generic macro has the same name as the function. These type-generic macros are:

atan2() fma() llround() remainder()
cbrt() fmax() log10() remquo()
ceil() fmin() log1p() rint()
copysign() fmod() log2() round()
erf() frexp() logb() scalbn()
erfc() hypot() lrint() scalbln()
exp2() ilogb() lround() tgamma()
expm1() ldexp() nearbyint() trunc()
fdim() lgamma() nextafter()
floor() llrint() nexttoward()

If all arguments for generic parameters are real, then use of the macro invokes a real function; otherwise, use of the macro results in undefined behavior.

For each unsuffixed function in the <complex.h> header that is not a c-prefixed counterpart to a function in the <math.h> header, the corresponding type-generic macro has the same name as the function. These type-generic macros are:

carg()
cimag()
conj()
cproj()
creal()

Use of the macro with any real or complex argument invokes a complex function.

Functions invoked by use of type-generic macros are invoked with the declarations listed below.

#include <tgmath.h>
int n;
float f;
double d;
long double ld;
float complex fc;
double complex dc;
long double complex ldc;

The following are the type-generic macros that invoke the functions that are invoked with the preceding declarations.

See attributes(5) for descriptions of the following attributes:

modf(3M), complex.h(3HEAD), math.h(3HEAD), cabs(3M), fabs(3M), attributes(5), standards(5)