Hi,
Using this Shared Object:
#include <stdio.h>
#include <stdlib.h>
int int_print (int i)
{
printf("%dn", i);
return(0);
}
int float_print (float f)
{
printf("%fn", f);
return(0);
}
...and the following newLisp code:
#!/usr/bin/newlisp
(import "./lib.so" "int_print")
(import "./lib.so" "float_print")
(int_print 345)
(float_print 1.2)
(exit)
...delivers this result:
345
0.000000
It seems that passing a float to a C function does not work? Or is there something wrong in the code?
Also, is it possible to pass an array to a C function?
Peter
Passing an INT array to a C function works:
C-code:
int array_print (int i[])
{
printf("%dn", i[0]);
printf("%dn", i[1]);
return(0);
}
--------------------------------------------------
NewLisp:
(import "./lib.so" "array_print")
(array_print (append (pack "lu" 16432) (pack "lu" 54321)))
An array with floats also works fine this way. Now for the single floats.... ;-)
I've seen this error (%f and double) or (%lf and float) many times in plain C. I bet if you change float to double you will have no problem.
Eddie
No; suppose I change my C-function this way:
int float_print (float f)
{
printf("%fn", f);
printf("%gn", f);
printf("%en", f);
return(0);
------------------------------------------
(import "./float.so" "float_print")
(float_print 1.2)
}
Then the result is:
0.000000
4.17233e-08
4.172325e-08
Strange! Also PACKing within newLisp does not help me here.
Yes, but doesn't newlisp use doubles internally and not floats?
in (float_print 1.2) the 1.2 is being passed as a double isn't it?
Eddie
So you mean it's never going to work anyway?
Even if it is passed as double, at least one of the PRINTF modifiers should show the number correctly then?
looks like an "Endian" issue to me...
int float_print(double num)
{
printf(">>%lf<<", num);
return(0);
}
gcc test.c -shared -o testlib.so
newLISP v.8.2.6 Copyright (c) 2004 Lutz Mueller. All rights reserved.
> (import "/usr/home/nuevatec/testlib.so" "float_print")
float_print <281A153C>
> (float_print 1.234)
>>1.234000<<0
>
Eddie is right: newLISP uses double
Lutz
never take a posting too literaly...:-)
> (unpack "lf" 1.2)
Segmentation fault
:-)
Yes I understand, but this is too bad; it means that many C-library's cannot accept a 'float' coming in from newLisp. There are functions which declare their arguments as float, I cannot pass float values to them.
yes you can:
(get-integer (pack "f" 1.23)) => 1067282596
The integer coming out is what you pass to the function which takes float.
Lutz
Great! This is what I was looking for.
Thanks Lutz!!
Sorry doesn't work ... but should ... investigating ...
Lutz
.. its floating segmf's today...:-)
> (get-integer (get-float (pack "lf" (float 12314127.641234))))
Segmentation fault
Works just fine, I forgot to compile:
#include <stdio.h>
int float_print(float num)
{
printf(">>%f<<", num);
return(0);
}
> (import "/usr/home/nuevatec/testlib.so" "float_print")
float_print <281A153C>
> (float_print (get-integer (pack "f" 1.234)))
>>1.234000<<0
>
Lutz
I don't want to be disturbing but it works for me!
int float_print (float f)
{
printf("%fn", f);
printf("%gn", f);
printf("%en", f);
return(0);
}
-----------------------------------------------
NewLisp:
(import "./float.so" "float_print")
(float_print (get-integer (pack "f" 1.23)))
Result:
1.230000
1.23
1.230000e+00
Norman, Norman ... too much of that dark beer ;)
Lutz
yes, it works just fine, I forgot to compile
Lutz
Yeah he is drinking too much... ;-)
Yes we call it "Dentergems Double" But it floats good ;-)
I am still waiting for that case of "Dentergems Double" you guys promised me some time ago ...
Lutz
Heee Lutz yes your right ;-)
Pjot..how about it? Your traveling to the states next week!
Cant you post a case for Lutz?
Well, I will be in Utah, not Florida unfortunately... ;-)
In Utah on Sundays they don't serve beer with more than 6% alcohol content . In Florida they don't sell beer in supermarkets before noon on Sundays (so people don't come drunken to church :) )
Lutz
hahahah..sounds logic... Well here in The Netherlands we have this standard
environment-rule "where a church is is a bar" ;-) So actualy every town with a church
has the bar across the street ;-) Im wont explain the results ;-)