TGMATH(3)              FreeBSD Library Functions Manual              TGMATH(3)

NAME
     tgmath - type-generic macros

SYNOPSIS
     #include <tgmath.h>

DESCRIPTION
     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,
     respectively, 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
     implementation.

     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
     called.

           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>.

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

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

COMPILER SUPPORT
     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
     compilers that support this keyword, this header file works with GCC.

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

FreeBSD 13.1-RELEASE-p6         January 4, 2012        FreeBSD 13.1-RELEASE-p6