Test for infinity
#include <math.h> #define isinf ( x ) ...
libm
Use the -l m option to qcc to link against this library.
The isinf() macro tests to see if a number is “infinity.”
#include <stdio.h> #include <errno.h> #include <inttypes.h> #include <math.h> #include <fpstatus.h> int main(int argc, char** argv) { double a, b, c, d; a = 2; b = -0.5; c = NAN; fp_exception_mask(_FP_EXC_DIVZERO, 1); d = 1.0/0.0; printf("%f is %s \n", a, (isinf(a)) ? "infinite" : "not infinite"); printf("%f is %s \n", b, (isinf(b)) ? "infinite" : "not infinite"); printf("%f is %s \n", c, (isinf(c)) ? "infinite" : "not infinite"); printf("%f is %s \n", d, (isinf(d)) ? "infinite" : "not infinite"); return(0); }
produces the output:
2.000000 is not infinite -0.500000 is not infinite NAN is not infinite Inf is infinite
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |