Re: variables arguments

Victor Bazarov wrote:


Probably i did not gazing read. I think the trouble can be only to access to
"..." params inside C++ function. Do not speak, that OP can not write as
exmple below.

Really, I do not why no standard way to lunch boo, so OP can make own
function to lunch.

-- cut here --

#include <stdio.h>
#include <stdarg.h>

typedef unsigned uint;

// ************************************
// ************************************
extern "C" void boo(uint size, ...)
{
va_list argptr;
va_start(argptr, size);

 printf("boo: ");
 for(uint i=size; i; --i){ printf("%u ",va_arg(argptr,uint) ); }
 if(size)printf("\n");

va_end(argptr);
}

// ************************************
// ************************************
#define FIXED_ARRAY_SIZE
#define ARRAY_SIZE (1024)

extern "C" void foo(uint size, ...)
{
 if(!size){ boo(size); return; }

//the most simple way
// ************************************
#ifdef FIXED_NUM_OF_PARAMS

uint *buf=0;
try{
 buf=new uint[size];
uint *ptr=buf;

va_list argptr;
va_start(argptr, size);

 for(uint i=size; i; --i){ *ptr++=va_arg(argptr,uint); }

va_end(argptr);

 switch(size)
  {
   case 1: boo(size,buf[0]); break;
   case 2: boo(size,buf[0],buf[1]); break;
   case 3: boo(size,buf[0],buf[1],buf[2]); break;
   case 4: boo(size,buf[0],buf[1],buf[2],buf[3]); break;
   case 5: boo(size,buf[0],buf[1],buf[2],buf[3],buf[4]); break;
   default:
    throw "overflow";
  }

}catch(...){delete[] buf; throw;}
#endif

// ************************************
#ifdef FIXED_ARRAY_SIZE

struct Buf
{
 uint array[ARRAY_SIZE];
};

Buf buf;
uint *ptr=buf.array;

va_list argptr;
va_start(argptr, size);

 for(uint i=size; i; --i){ *ptr++=va_arg(argptr,uint); }

va_end(argptr);

 boo(size,buf);
/*
  //alloc stack area
  b4: 81 ec 0c 10 00 00 sub $0x1000,%esp

  //fill stack area
  bd: 89 e0 mov %esp,%eax
  bf: 52 push %edx
  c0: 52 push %edx
  c1: 68 00 10 00 00 push $0x1000
  c6: 56 push %esi
  c7: 50 push %eax
  c8: e8 33 ff ff ff call _memcpy
  cd: 83 c4 14 add $0x14,%esp

  //push size
  d0: 53 push %ebx
  d1: e8 3a ff ff ff call 10 <_boo>

  //free stack area
  d6: 81 c4 10 10 00 00 add $0x1000,%esp

// ***********************
In example "boo(size,buf);" constant $0x1000 can be runtime value

if not, that "boo(size,buf);" can be implemented as external
"C-linkage" user function implemented with external ASM

extern "C" void lunch(uint size, uint *buf, void *boo);
really, I do not why no standard way to lunch boo

*/
#endif

// ************************************
#ifdef EXIST_ASM

asm{

 //alloc stack area
 subl size,%esp

 //fill stack area
 movsl (buf->%esp)[size]
 pushl size
 call _boo
 popl %eax

 //free stack area
 addl size,%esp

}

#endif

}

// ************************************
// ************************************
int main()
{
 foo(0);
 foo(1,1);
 foo(2,1,2);
 foo(3,1,2,3);
 foo(4,1,2,3,4);
 foo(5,1,2,3,4,5);
}

-- cut here --

--
Maksim A. Polyanin

"In thi world of fairy tales rolls are liked olso"
                               /Gnume/