#include <stdio.h>
#include <stdlib.h>
int main(){
        char buff[]="\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A"
(*(void(*)())buff)();
}
b$ gcc buff.c -o buff
buff.c: In function ‘main’:
buff.c:18:14: error: called object is not a function or function pointer
  char buff[]="\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A"
              ^

    

Perhaps your google search box is broken? Hehe. I took less than 20 seconds to find an answer. I thought about not posting it but that would be cruel. So since the work is done:

http://stackoverflow.com/questions/28901223/c-casting-char-array-to-an-integer-pointer

Oh man, you're just missing a semicolon (at the end of your string). Lol, that's an annoying mistake to spend a lot of time fixing.

revolution, he's trying to cast to a function pointer, so he can call the array as a function.

C is so dumb about this IMO. End of line means end of expression, and if you want to extend the line use a backslash. Haha, just my uninformed opinion on C and how it "should" be.

Okay, it is all a mystery to me, all those brackets and asterisks just to call some code are mighty confusing.

To be fair, it's not really something you should ever need to do. Semantically, OP is creating a character array and trying to "call" the contents of the array as if it were the machine code of a function.

I use the FASM compiler to extract the binary to the gcc ompiler to use, prompt error pointer. ....

Code:

  char buff[]="\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A"
  (*(void(*)())buff)();}    

  char buffer[] = "\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A";
int main(){
  void (*buff)(); // define a function pointer variable
  buff = (void *)buffer; // assign the (cast) address of the buffer to it
  buff(); // call the buffer contents as a function
}
    

  jmp buffer    

  return buff();    

  int(*buff)();    

return ((int (*)(void))buffer)();    

Oh man, you're just missing a semicolon (at the end of your string). Lol, that's an annoying mistake to spend a lot of time fixing.

Btw, I tested it and it segfaulted. I'm guessing either your code is buggy or the data section might be marked non-executable on my OS (Linux x64).

If all you want is to link to some assembly, there are much easier ways to go about this.

revolution, he's trying to cast to a function pointer, so he can call the array as a function.

kerr wrote:

I use the FASM compiler to extract the binary to the gcc ompiler to use, prompt error pointer. ....

Code:

  char buff[]="\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A"
  (*(void(*)())buff)();}    

Code:

  char buffer[] = "\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A";
int main(){
  void (*buff)(); // define a function pointer variable
  buff = (void *)buffer; // assign the (cast) address of the buffer to it
  buff(); // call the buffer contents as a function
}
    

Compiled with 03 (maximum optimization)

Code:

  jmp buffer    

Of course this particular code in the buffer won't actually work as a function.
To be perfectly correct buff should return an int and main should end with

Code:

  return buff();    

and be defined as

Code:

  int(*buff)();    

int main()
{
        my_func();

        return 0;
}    

        format ELF64

        public my_func

my_func:

        ret    

rm -v *.exe
rm -v *.o

fasm my.fasm my.fasm.o

gcc -c my.c -o my.c.o

gcc my.c.o my.fasm.o -o my.exe    

If the intention is to hide asm in C then please ignore everything below
----
It's easier (and more flexible i.e. msvc 64 or other architectures) to split the asm and C parts:

my.c

Code:

int main()
{
        my_func();

        return 0;
}    

my.fasm

Code:

        format ELF64

        public my_func

my_func:

        ret    

Shell:

Code:

rm -v *.exe
rm -v *.o

fasm my.fasm my.fasm.o

gcc -c my.c -o my.c.o

gcc my.c.o my.fasm.o -o my.exe    

For gdb simply 'set disassembly-flavor intel' and use 'layout asm' or 'layout split'

 char *buff="\xB0\x04\xB3\x01\x59\x66\xBA\x10\x00\xCD\x80\xB0\x01\xB3\x00\xCD\x80\xE8\xEA\xFF\x68\x65\x6C\x6C\x6F\x20\x77\x6F\x72\x6C\x64\x21\x0A"
  (*(void(*)())buff)();}

this is ok!