Thread: printf conversion characters for long longs.

What is the printf conversion character for a long long? And the one for a long double? I just noticed that %d and %x.f (x number of decimal places) don't work with long longs and long doubles.

Thanks.

ll (two lowercase L) for a long long int, L for a long double (in standard C99 at any rate).

Using minGW on windows? See here;
http://coding.derkeiler.com/Archive/.../msg04086.html

Originally Posted by samus250

Yup, that's me, MinGW on Windows. But I still didn't get the conversion character I need for the printf function from that post.

That's because there isn't one. The MS runtime doesn't support the 10-byte long double that gcc uses. To print it, cast it to a double and hope that it's within range.
http://www.mingw.org/MinGWiki/index.php/long%20double

Or I suppose you could write your own printf-like function just for long doubles....

Originally Posted by tabstop

That's because there isn't one. The MS runtime doesn't support the 10-byte long double that gcc uses. To print it, cast it to a double and hope that it's within range.
http://www.mingw.org/MinGWiki/index.php/long%20double

Or I suppose you could write your own printf-like function just for long doubles....

Crap.

Just for you (and for me, since I have MinGW on Windows, too), this appears to work -- although I hacked it together in the last ten minutes so you never know:

Code:

char *printf_ld(long double arg, char answer[15]) {

    /* For my own sake: scientific notation with six digits */
    double mantissa, exponent, lg;
    lg = log10l(fabs(arg));
    exponent = floor(lg);
    mantissa = pow(10, lg-exponent);
    mantissa = copysign(mantissa, arg);
    sprintf(answer, "%.6fe%+04g", mantissa, exponent);
    return answer;
}

Use at your own peril.

Cool, thanks a lot! I'll give a look at that.