Re: C23 thoughts and opinions

On Fri, 31 May 2024 15:04:46 +0100
bart <bc@freeuk.com> wrote:

On 31/05/2024 14:48, Michael S wrote:

On Fri, 31 May 2024 16:28:11 +0300
Michael S <already5chosen@yahoo.com> wrote:
 

On Fri, 31 May 2024 16:19:37 +0300
Michael S <already5chosen@yahoo.com> wrote:
 

>
No, it does not work like that.
First, copy *exactly* what I said in my previous post.
Only after you reproduced, start to be smart.
_binary_hello_c_size is a link simbol rather than variable.
>
Declaration:
extern char _binary_hello_c_size[];
>
Usage:
   printf("%zd\n", (size_t)_binary_hello_c_size);
   

>
Thinking about it, I could be wrong.
I should test more, with less small program.
 

 
I tested with bigger program, and it's still works.
So, what written above is correct.
 

 
Can you show the full program and the full process?

test_objcopy.c:
#include <stdio.h>

int data1[42] = { 1,2,3 ,4,5};
extern unsigned char _binary_test_bi_start[];
extern unsigned char _binary_test_bi_end[];
extern unsigned char _binary_test_bi_size[];

extern unsigned char _binary_bin_to_list_c_start[];
extern unsigned char _binary_bin_to_list_c_end[];
extern unsigned char _binary_bin_to_list_c_size[];

int main()
{
  printf("%-40s %p %zd\n", "_binary_test_bi_start",
    _binary_test_bi_start, (size_t)_binary_test_bi_start);
  printf("%-40s %p %zd\n", "_binary_test_bi_end",
    _binary_test_bi_end, (size_t)_binary_test_bi_end);
  printf("%-40s %p %zd\n", "_binary_test_bi_size",
    _binary_test_bi_size, (size_t)_binary_test_bi_size);
  printf("%-40s %p %zd\n", "_binary_bin_to_list_c_start",
    _binary_bin_to_list_c_start, (size_t)_binary_bin_to_list_c_start);
  printf("%-40s %p %zd\n", "_binary_bin_to_list_c_end",
    _binary_bin_to_list_c_end, (size_t)_binary_bin_to_list_c_end);
  printf("%-40s %p %zd\n", "_binary_bin_to_list_c_size",
    _binary_bin_to_list_c_size, (size_t)_binary_bin_to_list_c_size);
  return 0;
}

Test files: test.bi and bin_to_list_c.
Conversion to ojects:
objcopy -I binary -O elf64-x86-64 test.bi test_bi.o
objcopy -I binary -O elf64-x86-64 bin_to_list.c test_c.o

Compilation:
gcc -s -Wall -Oz test_objcopy.c test_bi.o test_c.o

I compiled with additional option -Xlinker -Map=test_objcopy.map
in order to make myself sure tha *_size are indeed pure symbols that
have no memory allocated underneaths.