Hi,
I am trying to use Fiddle to call C function in dynamic library, I used to
be able to
pass a return long variable and an error message, but now only return long
variable
is returned, can't get the error message, I create a very simple example to
test,
this is my add.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
long add(long maxn, double delta, double conf, char *errMsg)
{
long answer;
errMsg = (char *) malloc(6*sizeof(char));
answer = (long)(maxn + delta + conf);
errMsg = "Hello!";
return answer;
}
and add.h
#ifndef add_h
#define add_h
long add(long maxn, double delta, double conf, char *errMsg);
#endif
I created lib_add.so and part of my .rb file calling fiddle:
class SamplesizeController < ApplicationController
require 'fiddle'
.....
def compute
str = "there!"
libm = Fiddle.dlopen('/var/www/myapp/smart/lib/lib_add.so')
add = Fiddle::Function.new(libm['add'],[Fiddle::TYPE_LONG,
Fiddle::TYPE_DOUBLE,
Fiddle::TYPE_DOUBLE,
Fiddle::TYPE_VOIDP],
Fiddle::TYPE_LONG)
add.call(session[:nmax], session[:delta], session[:conf], str)
session[:errmsg] = str.to_s
redirect_to :action => "results"
end
....
end
session[:errmsg] can be modified? only return variable can be changed or
something I did
was wrong? Any advice will be greatly appreciated.
Thanks!
Liz
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