get the address of a function??

[John]

Is the following program print the address of the function?

void hello()
{ printf("hello\n");
}

void main()
{
printf("hello function=%d\n", hello);
}

please advice. thanks....

[Harald van Dijk]

Jordan Abel wrote:

2006-11-05 <wm***************************@JUPITER1.PC-ROSENAU.DE>,
Herbert Rosenau wrote:

On Sat, 4 Nov 2006 22:19:44 UTC, Jordan Abel <ra****@random.yi.org>
wrote:

2006-11-04 <11*********************@h54g2000cwb.googlegroups. com>,
ma*****@gmail.com wrote:
Could dlsym() be considered a valid way of doing this? At least for the
POSIX-compliant compilers/systems?

Not really. on a POSIX system, or really anything that supports dlsym,
conversion between function pointers and void * is defined anyway.

No. void* may even not wide enough to hold an address of a function.

On a POSIX system, it is. It's in that _other_ standard, you know? So
using dlsym (which is the reason why POSIX requires it) trickery for
this purpose is beyond silly. Either it'll work or dlsym() won't.

dlsym() is part of the XSI extension to POSIX, not of POSIX itself. (I
know a lot of people posted that POSIX requires it, so this is not
directed at you in particular.)

[Jordan Abel]

2006-11-06 <11**********************@k70g2000cwa.googlegroups .com>,
Harald van D?k wrote:

Jordan Abel wrote:

>2006-11-05 <wm***************************@JUPITER1.PC-ROSENAU.DE>,
Herbert Rosenau wrote:

On Sat, 4 Nov 2006 22:19:44 UTC, Jordan Abel <ra****@random.yi.org>
wrote:

2006-11-04 <11*********************@h54g2000cwb.googlegroups. com>,
ma*****@gmail.com wrote:
Could dlsym() be considered a valid way of doing this? At least for the
POSIX-compliant compilers/systems?

Not really. on a POSIX system, or really anything that supports dlsym,
conversion between function pointers and void * is defined anyway.

No. void* may even not wide enough to hold an address of a function.

On a POSIX system, it is. It's in that _other_ standard, you know? So
using dlsym (which is the reason why POSIX requires it) trickery for
this purpose is beyond silly. Either it'll work or dlsym() won't.

dlsym() is part of the XSI extension to POSIX, not of POSIX itself. (I
know a lot of people posted that POSIX requires it, so this is not
directed at you in particular.)

Well, my point was rather "dlsym is never useful for this, because if
dlsym is available, you can cast it to void* anyway", so it still
stands. (And I seem to recall that POSIX still requires function pointer
to void*, but I could be wrong)

[Richard Bos]

CBFalconer <cb********@yahoo.comwrote:

Simon Biber wrote:

There is no lack of knowledge of the size involved. You can get it from
sizeof. Either sizeof f, or sizeof (int(*)(void)).

I don't think so. A function pointer may be a large involved
thing, such as fields for segment, offset, in/out_ofmemory, etc. I
don't think sizeof can cope with this.

If it didn't, you couldn't have arrays of function pointers.

Richard

[Joe Wright]

Richard Bos wrote:

CBFalconer <cb********@yahoo.comwrote:

>Simon Biber wrote:

>>There is no lack of knowledge of the size involved. You can get it from
sizeof. Either sizeof f, or sizeof (int(*)(void)).

I don't think so. A function pointer may be a large involved
thing, such as fields for segment, offset, in/out_ofmemory, etc. I
don't think sizeof can cope with this.

If it didn't, you couldn't have arrays of function pointers.

Richard

Very good point. Bos is boss. :-)

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Richard Bos]

Joe Wright <jo********@comcast.netwrote:

Richard Bos wrote:

CBFalconer <cb********@yahoo.comwrote:

Simon Biber wrote:
There is no lack of knowledge of the size involved. You can get it from
sizeof. Either sizeof f, or sizeof (int(*)(void)).
I don't think so. A function pointer may be a large involved
thing, such as fields for segment, offset, in/out_ofmemory, etc. I
don't think sizeof can cope with this.

If it didn't, you couldn't have arrays of function pointers.

Very good point. Bos is boss. :-)

No, Bos is Wood.

Richard