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red hat 9.0 gcc (ceil, floor and sqrt function errors) ??

hi !

I just recently started working in linux red hat 9.0 to compile my C programs , I am using the gcc command but the program is giving me weird errors and does not recognize the functions ceil(), floor() and sqrt(), I have tried and added most header files like math.h nad stdlib.h along with stdio.h but I keep getting wried errors like :

Quote:

/tmp/ccqz1JFE.o(.text+0xba): In function `main':
: undefined reference to `sqrt'
collect2: ld returned 1 exit status

The program is as follows
#include<stdio.h>
#include<stdlib.h>
#include<math.h>

Code:

int main()

{

        double i, j, k;

        for(j = 0.0; j < 1.0; j += 0.1)

                printf("%8.1f", j);

        printf("\n");

        for(i = 0.0; i < 10.0; i += 1.0)

        {

                for(j = 0.0; j < 1.0; j += 0.1)

                {

                        k = i + j;

                        printf("%8.1f", sqrt(k));

                }

                printf("\n");

        }

        return 0;

}

These are linker errors, not compiler errors; hence the “ld”. You will find these functions in the m (maths) library (/usr/lib/libm.so), and you can make this compile using:

Code:

gcc -lm infile.c outfile

A header file only includes the declaration of a function; you need to link your program against the implementation of the function in order to generate a usable binary.

To find out which header file a function is declared in, just look at its manpage:

Code:

man ceil