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Why sin function doesn't work?

I'm using my personal linux laptop that I purchased a year ago to write following c program in vim editor: The operating system is Ubuntu.

#include <stdio.h>
#include <math.h>

int main( )
{
   double x;
   float y;

   x = 45.0;                  /* 45 degrees */
   x *= (3.141593 / 180.0);

   y = sin(x);
   printf ("The result is: %f\n", y);

   return 0;
}

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When I compile, I get the following error:
/tmp/ccDTU7GW.o: In function `main':
first.c:(.text+0x39): undefined reference to `sin'
collect2: error: ld returned 1 exit status

In /usr/include folder, there is math.h but I didn't find any sin function prototypes in this file.

ASKER CERTIFIED SOLUTION

phoffric

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noci

Much info can be found in the manual pages....
Man sin starts with:



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.


   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
.....

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Which tells you that you need the include file math.h and what library to link with.
For most functions such a page exists. For those that don't have it the provider of the library will have some form of documentation.

in general if a library has been provided as: libxyz.so then you can specify it on the link command with -lxyz (gcc compiler with linkage included will accept those and pass them on to the linker (ld)

naseeam

ASKER

@noci
Thank you so much for providing another great solution. I didn't see it until now.

SOLUTION

noci

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