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TGMATH(3)		 BSD Library Functions Manual		     TGMATH(3)

     tgmath -- type-generic macros

     #include <tgmath.h>

     The header	<tgmath.h> provides type-generic macros	for <math.h> and
     <complex.h> functions that	have float (suffixed with f), double and long
     double (suffixed with l) versions.	 The arguments that vary across	the
     three functions and have type float, double and long double, respec-
     tively, are called	generic	arguments.

     The following rules describe which	function is actually called if a type-
     generic macro is invoked.	If any generic argument	has type long double
     or	long double complex, the long double function is called.  Else,	if any
     generic argument has type double, double complex or an integer type, the
     double version is invoked.	 Otherwise, the	macro expands to the float im-

     For the macros in the following table, both real and complex functions
     exist.  The real functions	are prototyped in <math.h> and the complex
     equivalents in <complex.h>.  The complex function is called if any	of the
     generic arguments is a complex value.  Otherwise, the real	equivalent is

	   Macro      real function	  complex function
	   acos()     acos()		  cacos()
	   asin()     asin()		  casin()
	   atan()     atan()		  catan()
	   acosh()    acosh()		  cacosh()
	   asinh()    asinh()		  casinh()
	   atanh()    atanh()		  catanh()
	   cos()      cos()		  ccos()
	   sin()      sin()		  csin()
	   tan()      tan()		  ctan()
	   cosh()     cosh()		  ccosh()
	   sinh()     sinh()		  csinh()
	   tanh()     tanh()		  ctanh()
	   exp()      exp()		  cexp()
	   log()      log()		  clog()
	   pow()      pow()		  cpow()
	   sqrt()     sqrt()		  csqrt()
	   fabs()     fabs()		  cabs()

     No	complex	functions exist	for the	following macros, so passing a complex
     value to a	generic	argument invokes undefined behaviour:

	   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()

     The following macros always expand	to a complex function:

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

     This header includes <complex.h> and <math.h>.

     The header	<tgmath.h> conforms to ISO/IEC 9899:1999 ("ISO C99").

     The header	<tgmath.h> first appeared in FreeBSD 5.3.

     Before ISO/IEC 9899:2011 ("ISO C11"), the header <tgmath.h> could not be
     implemented with strictly conforming C code and needed special compiler
     support.  As of ISO/IEC 9899:2011 ("ISO C11"), this header	file can be
     implemented using the _Generic() language keyword.	 In addition to	com-
     pilers that support this keyword, this header file	works with GCC.

     Many of the functions mentioned here are not prototyped in	<math.h> or
     <complex.h> as they are not yet implemented.  This	prevents the corre-
     sponding type-generic macro from working at all.

BSD				January	4, 2012				   BSD


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