char getLine(char **line);

int main(int argc, char *argv[])
{
    char *line;
    char returnVal = 0;

    returnVal = getLine(&line);
    printf("%s", line);

    free(line);

    system("pause");
    return 0;
}

char getLine(char **line) {
    unsigned int lengthAdder = 1, counter = 0, size = 0;
    char charRead = 0;

    *line = malloc(lengthAdder);
    while((charRead = getc(stdin)) != EOF && charRead != 'n')
    {
        *line[counter++] = charRead;
        *line = realloc(*line, counter);
    }

    *line[counter] = '';

    return charRead;
}

void getLine(char **line)
{
    *line = malloc(length);

    // etc.
}

char *line;
getLine(&line);

char *tmp;
...
tmp = realloc(line, counter);
if(tmp == NULL)
   ERROR, TRY TO SOLVE IT
line = tmp;