https://issues.dlang.org/show_bug.cgi?id=12547

--- Comment #1 from Don <clugdbug@yahoo.com.au> ---
FYI: They are defined to return floating-point values because that's what the equivalent C functions do. They should not be modified.

Note that if you cast them to integers, you have to worry about overflow. So that's more complicated.

Note also the existence of rndint() and rndlong().

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https://issues.dlang.org/show_bug.cgi?id=12547

--- Comment #2 from bearophile_hugs@eml.cc ---
(In reply to Don from comment #1)

> FYI: They are defined to return floating-point values because that's what the equivalent C functions do. They should not be modified.

Perhaps lovers of C functions can use core.stdc.math:

void main() {
    import core.stdc.math;
    double x = 2.7;
    int y1 = cast(int)floor(x);
    int y2 = cast(int)ceil(x);
    int y3 = cast(int)round(x);
}


But perhaps new functions can be defined in Phobos, with a different name (possibly with a clear name).


> Note that if you cast them to integers, you have to worry about overflow. So that's more complicated.

In the cases where you care about overflow can't you use to! function?


void main() {
    import std.math, std.conv;
    double x = 1e100;
    int y1 = x.floor.to!int;
}


> Note also the existence of rndint() and rndlong().

I don't know where they are, sorry for my ignorance. Do you mean stuff like
this?
http://opensource.apple.com/source/Libm/Libm-93/ppc.subproj/rndint.c

In std.math I have found this:

pure nothrow @safe long rndtol(real x);
    Returns x rounded to a long value using the current rounding mode. If the
integer value of x is greater than long.max, the result is indeterminate.

But what about ints, or floor/ceil? (And usually functions with name that starts with "rnd" are for random generation).

Thank you Don for your answers.

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https://issues.dlang.org/show_bug.cgi?id=12547

--- Comment #3 from bearophile_hugs@eml.cc ---
In Python 3.4 those functions return an int (but Python has multiprecision
integers):

from math import ceil
print(type(ceil(1.5)))


Output:

<class 'int'>

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https://issues.dlang.org/show_bug.cgi?id=12547

Iain Buclaw <ibuclaw@gdcproject.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P4

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