void * to char *

**Loukoulaylay** · 04-10-2009

Hi there, i got this function : and i most convert the (void*) returned by the function in a (char *). I tried many things, but nothing could go past the compiler.. can anyone give me a hint on this?

my last try was something like: (char*)function_result
where function_result is the void* returned by the function.

Code:

typedef struct
{
  int nombre_prefere; 
  char allo[50];	  
  char *chaine_dynamique;
} MaStructure;

void *recuperateur_de_allo(void *donnees)
{
  MaStructure *d = donnees;
  return d->allo;
}

I give you my big thanks!

**quzah** · 04-10-2009

It helps if you make a small example of what you're trying to compile.

Code:

#include<stdio.h>
struct foo
{
    char bar[ 10 ];
};

void * baz( void * foo )
{
   return ((struct foo *)foo)->bar;
}

int main( void )
{
    struct foo bar;
    char *fbb;

    fbb = (char *) baz( &bar );
    return 0;
}

Quzah.

**Loukoulaylay** · 04-10-2009

Sorry, your right. Here an exemple that represent my problem.

Code:

#include<stdio.h>
struct foo
{
    char bar[ 10 ];
};

void * baz( void * foo )
{
   return ((struct foo *)foo)->bar;
}

char *main( (*baz)(void *))
{
    struct foo bar;

    return = (char *) baz( &bar );
}

**quzah** · 04-10-2009

Look at my example, and compare it to yours. What parts are you confused about?

Quzah.

**MK27** · 04-10-2009

Clue: This is not how to call a function

Code:

return = (char *) baz( &bar );

**Loukoulaylay** · 04-10-2009

at the line: return = (char *) baz( &bar );

i get this error : 'void' term to non-'void'

Clue: This is not how to call a function

event with this clue i just can't see it right now

. I been scripting 36 hours straight for school. heh

Thx for helping me guys.

**quzah** · 04-10-2009

Why did you change that line from what I had? You must have had a reason. What was it?

Quzah.

**Loukoulaylay** · 04-10-2009

i changed the "char *main( (*baz)(void *))" too. it's exactly like what i use it in my program. Since I'm still a beginner, i prefer showing an example really similar to the real thing.

**MK27** · 04-10-2009

Originally Posted by Loukoulaylay

I been scripting 36 hours straight for school. heh

In C? Are you sure? Maybe it is time to quit before you grow old!

Just kidding. My point is you are complaining about how to typecast a return value, but you are not really using the return value at all. That would be:

Code:

struct foo bar;
char ptr*;
ptr = (char *) baz( &bar );
return 0;

The return value of main is not used during the execution; it's for the OS, and it should be an int, not a char. Which brings us to this:

Code:

char *main( (*baz)(void *))

What is that supposed to mean???

**Loukoulaylay** · 04-10-2009

In C? Are you sure? Maybe it is time to quit before you grow old!

I must agree with that. That is the last time i take a C course as an option at University..heh

yeah, i do know that. I just used the main for the example, but in my "real case" it's an another function which return char *main( (*baz)(void *)).

so i guess that's not my problem

, but you guys still gave my clues. My thinking wasn't all wrong since i did the same thing as you when i tried ^^.

**MK27** · 04-10-2009

In any case, "return=" is non-sensical.

Using a (char*)typecast should be enough if you have the rest of your syntax in order.

Next time don't wait til the end of the semester to start coding!

**Loukoulaylay** · 04-10-2009

lol i didn't wait till the end. i Just haev 3 big project to do during the semester .. and i just received the last one. I still got 1 week to finish it, but i wan to clear it right aways.

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