Getlinefunction-Allocate- memory on runtime

/*Author-XAgent Smith*/
/*Date:Step 25,2018*/
#include <stdio.h>
#include <stdlib.h>
/*Start of getln fuction*/
void *reallo_c(char  ** c,size_t size,size_t len)
{
   char *k=NULL;
   short i=0;
   k=(char*)malloc(size*sizeof(char));
  while((( 0<=(len--)&&*((*c)+i)!='\0')?*(k+i++)=*(*(c)+i) : 0));
   free(*c);
   return k ;
}
char *getln(void)
{
    //Initializing variables and pointers
    const size_t sizeIncrement=5;
    char *buffer=(char*)malloc(5*sizeof(char));
    char *currentposition=buffer;
    size_t max_length=sizeIncrement;
    size_t length=0;
 static size_t L=0;
    char character;
    /*getting inputes*/
    while(1)
    {
        character=fgetc(stdin);//getting character from stdin file
        if(character=='\n') break;

        if(length>=max_length-1)
        {
            /*Allocating memory for next increment extra chararcter*/
            char *newbuffer=reallo_c(&buffer,(max_length+sizeIncrement),L-1);
            max_length+=sizeIncrement;
            if(newbuffer==NULL)
            {
                free(buffer);
                return NULL;
            }
            currentposition=newbuffer+L;
            buffer=newbuffer;
        }
        *(currentposition++)=character;
L++;
        length++;
    }
    *currentposition='\0';
    return buffer;
    /*End of getln function call*/
}

/*Start of main*/
int main()
{
    //calling getln();
    printf("%s\n",getln());
    return 0;
    /*End of main*/
}