har *
readUntilEOL( FILE *line )
{
    int cycle_counter = 1;
    char *buffer = NULL;
    char *buffer_saver = NULL; // if after realloc we lose memory
    if ( line == NULL ) {
        perror( "Empty file!" );
        return NULL;
    } else {
        const unsigned int BUFFER_SIZE = 1000000;
        buffer = calloc( BUFFER_SIZE, sizeof( *buffer ) );
        if ( buffer == NULL ) {
             perror( "Not enough memory for calloc" );
             return NULL;
        }
        do {
            buffer_saver = fgets( buffer + ( cycle_counter - 1 ) * ( BUFFER_SIZE - 1 ), BUFFER_SIZE, line );
            if ( buffer_saver == NULL ) {  // third  variant
                return buffer;
            }
            if ( ( strlen( buffer ) == 1 ) && ( buffer[0] == '\n' ) ) {  // if it's blank string
                free( buffer );
                return NULL;
            }
            if ( buffer[ strlen( buffer ) - 1 ] == '\n' ) {
                    return buffer;
            }
            cycle_counter++;
            buffer_saver = realloc( buffer, 1 + cycle_counter * ( BUFFER_SIZE - 1 ) * sizeof( *buffer ) );
            // we checked, that it's not EOL and EOF earlier, so we have at least one more symbol in line, so we have at least one byte of memory
            if ( buffer_saver == NULL ) {
                int memory_size = 1;
                buffer_saver = realloc( buffer,  memory_size + 1 + ( BUFFER_SIZE - 1 ) * ( cycle_counter - 1 ) * sizeof( *buffer )  );
                while ( buffer_saver != NULL ) {
                    buffer_saver = fgets( buffer + memory_size + ( cycle_counter - 1 ) * ( BUFFER_SIZE - 1 ), 1, line );
                    if ( buffer_saver == NULL ) {  // third  variant
                        return buffer;
                    }
                    if ( buffer[ strlen( buffer ) - 1 ] == '\n' ) {
                        return buffer;
                    }
                    memory_size++;
                    buffer_saver = realloc( buffer, ( memory_size + 1 + ( BUFFER_SIZE - 1 ) * ( cycle_counter - 1 ) * sizeof( *buffer ) ) );
                }
                perror( "Not enough memory for realloc." );
                free( buffer );
                return NULL;
            }
            buffer = buffer_saver;

        } while ( 1 );

    }
}