#include<math.h>

This is a discussion on #include<math.h> within the C Programming forums, part of the General Programming Boards category; Hi, I am working in linux Redhat7.1, P3 system. Whenever I compile a program which has a math function, I ...

  1. #1
    Registered User
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    Sep 2001
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    Unhappy #include<math.h>

    Hi,

    I am working in linux Redhat7.1, P3 system.

    Whenever I compile a program which has a math function, I use the command:

    cc filename.c -lm

    I have to do this inspite of including math.h

    The errors that were displayed when I didnot use -lm are as follows:::
    ***********************************************

    bash-2.04$ cc test.c
    /tmp/ccUQaDNH.o: In function `main':
    /tmp/ccUQaDNH.o(.text+0x1e): undefined reference to `sin'
    /tmp/ccUQaDNH.o(.text+0x4a): undefined reference to `sqrt'
    collect2: ld returned 1 exit status
    bash-2.04$ cc test.c -lm
    *---------------------------------------------

    What does this -lm signify and why should I give this.

    Ashesh

  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    not familiar with your compiler but my best guess would be that the compiler switch lm loads the maths library.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  3. #3
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    In addition to math.h which other *.h files will need me to add switches like "-lm"

    ashesh

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