Looking one char ahead when reading from file in C

I am aware that in c there are functions getc() and ungetc().

I would need this counter-function for fgetc(), sadly unfgetc() doesn't really exist. So I tried writting it on my own.

This is how it looks:

    int getNextChar(FILE* fd)

{
    // get the character
    int nextCharacter = fgetc(fd);

    // fseek it back, so you don't really move the file descriptor
    fseek(fd, -1, SEEK_CUR);

    // returning the char (as int)
    return nextCharacter;
}

But well... that doesn't seem to work.
I call it inside a while loop, like this.

while ( (c = fgetc(fd)) != EOF)
    {

        cx = getNextChar(fd);
        printf("%c", c);



    }

It gets stucked on the last character of the file (it prints it with every iteration to infinity). Now a little explanation why I need that in case that I'm doing it all wrong and that there would be another suitable solution.

I need to check the next character on being EOF. If it is EOF, I force send token, that is created in the while loop (this part is not important for my issue, so I didnt include it).

I am going through the loop and whenever I find a character that doesnt respond to a mask, I assume that I should send a token and start making a new one with that character that doesnt respond. Naturally, when I read the last char in the file, no next iteration will be done, therefore I won't send the last token. I need to check next char to be EOF. If it is EOF, I force send token.

Thank you for your advices!

Answer

You need to check that nextCharacter isn't EOF, since if it is, you'll still back off, thus causing the outer reading to never see the end of the file. Also check return values of more functions, like fseek().