#include <stdio.h>
#include <malloc.h>
#include <string.h>

char *getline2(FILE *f) {
    if(!f){
        return NULL;
    }
    unsigned char *mystring = malloc(1 * sizeof(unsigned char));
    int capacity = 1;
    if (fgets(mystring, capacity + 1, f) != NULL){
        puts(mystring);
        capacity *= 2;
    }
    while (fgets(mystring + capacity - 1 , capacity + 1, f) != NULL) {
        puts(mystring);
        capacity *= 2;
        unsigned char *tmp_mystring = malloc(capacity * sizeof(unsigned char));
        strncpy(tmp_mystring, mystring, strlen(mystring));
        mystring = malloc(capacity * sizeof(unsigned char));
        strncpy(mystring, tmp_mystring, strlen(tmp_mystring));
    }
    return mystring;
}

int main() {
    FILE *pFile;

    pFile = fopen("myfile.txt", "r");
    char* str = getline2(pFile);
//    puts(str);
    return 0;
}