Linux:using the the readline library [error] undefined reference to `readline'

sudo apt-get install libreadline-dev

1. #include <stdio.h>
2. #include <malloc.h>
3. #include <readline/readline.h>
4. 
5. void main(void){
6. 
7. char *line;
8. 
9. while( 1==1 ){
10.     line=readline("enter text>");
11.     printf("text: %s <\n",line);
12.     free(line);
13.     }
14. }

1. /tmp/cc6JYBvf.o: In function `main':
2. read_test.c:(.text+0xe): undefined reference to `readline'

gcc read_test.c -o read_test -lreadline