Using tan(), sin() etc.

[mavix]

How do I use the tan() and sin() functions in GCC? I included math.h, but returns an error message.

[Lord Illidan]

I think you have to compile it with the -lm option.

like gcc foo.c -o foo -lm

[MWAAAHAAA]

If you ever wonder about how to use a function, try the manual page. For example 'man sin' gives me the following:

SIN(3) Linux Programmer’s Manual SIN(3)

NAME
sin, sinf, sinl - sine function

SYNOPSIS
#include <math.h>

double sin(double x);
float sinf(float x);
long double sinl(long double x);

Link with -lm.

Yada, yada, yada

[56phil]

What do I need to install?


prh@phil-laptop:~$ man sin
No manual entry for sin

[xtacocorex]

You need to put std:: in front of sin, cos, and tan. That's if you didn't declare a namespace at the beginning of the code, which is not good practice if you are using more than one namespace in a code.

An example from my airfoil generation code:


PI=4.0*std::atan(1.0);
I did include cmath instead of math.h.


#include <cmath>
I didn't do any special linking in my compile and it works fine.

EDIT: Thought you were doing C++, so I don't know if cmath will work.

[Choad]

If you ever wonder about how to use a function, try the manual page. For example 'man sin' gives me the following:

SIN(3) Linux Programmer’s Manual SIN(3)

NAME
sin, sinf, sinl - sine function

SYNOPSIS
#include <math.h>

double sin(double x);
float sinf(float x);
long double sinl(long double x);

Link with -lm.

Yada, yada, yada
legend! i was wondering where the hell you find out about that stuff without just posting billions of threads on forums :rolleyes:

[Ragazzo]

What do I need to install?


prh@phil-laptop:~$ man sin
No manual entry for sin


manpages-dev

[daniminas]

Exist some basic guide or list of the parameters of Gcc?.. (then 'MAN')..

Thanks ;)