expm1, expm1f, expm1l


For the latest documentation on Visual Studio 2017, see Visual Studio 2017 Documentation.

For the latest documentation on Visual Studio 2017, see expm1, expm1f, expm1l on docs.microsoft.com. Computes the base-e exponential of a value, minus one.

double expm1(   
   double x   
float expm1(  
   float x  
);  // C++ only  
long double expm1(  
   long double x  
);  // C++ only  
float expm1f(  
   float x  
long double expm1l(  
   long double x  


The floating-point exponential value.

The expm1 functions return a floating-point value that represents ex – 1, if successful. On overflow, expm1 returns HUGE_VAL, expm1f returns HUGE_VALF, expm1l returns HUGE_VALL, and errno is set to ERANGE. For more information about return codes, see errno, _doserrno, _sys_errlist, and _sys_nerr.

Because C++ allows overloading, you can call overloads of expm1 that take and return float and long double values. In a C program, expm1 always takes and returns a double.

RoutineRequired header
expm1, expm1f, expm1l<math.h>

For additional compatibility information, see Compatibility.

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

Floating-Point Support
exp2, exp2f, exp2l
pow, powf, powl