Header File 

float.h 

Category 

Math Routintes 

Prototype 

double _chgsign(double d); 

long double _chgsignl(long double ld); 

Description 

Reverses the sign of a double-precision floating-point argument, d. 

_chgsignl is the long double version; it takes a long double argument and returns a long double result. 

Return Value 

Returns a value of the same magnitude and exponent as the argument, but with the opposite sign. There is no error return value. 

Portability