While the complex number support of D is great, I've noticed that phobos still lacks most math functions for complex numbers. In the mean time I thought I'd try importing some functions from C, but haven't had much luck with this.

Since you can import non-complex math functions by using the 'real' type directly, I thought you also might be able to do something like

extern (C) creal cexpl(creal);

but calling this just gives a segfault :( I've also tried calling the functions
with 24 byte structs (a gcc complex long double is 24 bytes, not 20 like creal)
but it still gives the occational segfault (I think it's messing up the stack.)

Anybody who can help me?

Nick

Nick wrote:

> but calling this just gives a segfault :( I've also tried calling the functions
> with 24 byte structs (a gcc complex long double is 24 bytes, not 20 like creal)
> but it still gives the occational segfault (I think it's messing up the stack.)

What do they do with the extra 4 bytes?

> 
> Anybody who can help me?
> 

I think somebody is currently working on math related functions.

In article <cej9ja$28nr$1@digitaldaemon.com>, parabolis says...
>
>Nick wrote:
>
>> but calling this just gives a segfault :( I've also tried calling the functions
>> with 24 byte structs (a gcc complex long double is 24 bytes, not 20 like creal)
>> but it still gives the occational segfault (I think it's messing up the stack.)
>
>What do they do with the extra 4 bytes?

A long double has two unused bytes, and a complex is composed of two of those. The two bytes take on semi-random values depending on which function created them and are ignored in any calculation. The 80 bit float is the maximum on Intel processors, so I guess they are reserved for other architectures.

Nick

Are you working with gcc?

"Nick" <Nick_member@pathlink.com> wrote in message news:cej7jg$285p$1@digitaldaemon.com...
> While the complex number support of D is great, I've noticed that phobos
still
> lacks most math functions for complex numbers. In the mean time I thought
I'd
> try importing some functions from C, but haven't had much luck with this.
>
> Since you can import non-complex math functions by using the 'real' type directly, I thought you also might be able to do something like
>
> extern (C) creal cexpl(creal);
>
> but calling this just gives a segfault :( I've also tried calling the
functions
> with 24 byte structs (a gcc complex long double is 24 bytes, not 20 like
creal)
> but it still gives the occational segfault (I think it's messing up the
stack.)
>
> Anybody who can help me?
>
> Nick
>
>

In article <cejibv$2c39$2@digitaldaemon.com>, Walter says...
>
>Are you working with gcc?
>
Nah, why'd you think that? :) I've just done some experimenting with complex numbers in C using gcc.

Nick

"Nick" <Nick_member@pathlink.com> wrote in message news:cejqit$2erh$1@digitaldaemon.com...
> In article <cejibv$2c39$2@digitaldaemon.com>, Walter says...
> >
> >Are you working with gcc?
> >
> Nah, why'd you think that? :) I've just done some experimenting with
complex
> numbers in C using gcc.

I suspect the problem is in the function return conventions used by the compiler. It's easy enough to check.