Using math.h

[tyr0]

Posted on February 16, 2016 at 15:49

Hello every one

I need to implement the code for STM32F, like the next lines: #include <stdlib.h> #include <math.h> ... int b; a= max(10, b) The compilation result is warning: implicit declaration of function 'max' [-Wimplicit-function-declaration] linking with -lm (or libm): undefined reference to `max' So... what is a problem here with using min/ max function?

[markb]

Posted on February 16, 2016 at 17:24 Hello, How about fmax()? AFAIK, max() isn't a standard function. Cheers, Mark

[Tesla DeLorean]

Posted on February 16, 2016 at 22:15

max() isn't a standard function.

Correct, though it is prevalent on Microsoft platforms as a macro in stdlib.h, it uses a lower case form, but I'm not a stickler for upper case macros. I just use these when I'm on more general or UNIX/LINUX platforms

#define min(a,b) (((a) < (b)) ? (a) : (b))
#define max(a,b) (((a) > (b)) ? (a) : (b))

[tyr0]

Posted on February 17, 2016 at 10:46

Thanks,

I got it I tried the macros. They are OK. Using fmax()/fmin() is not soo good because of floating calculations.

[tyr0]

Posted on February 17, 2016 at 10:48