Пример переделки кода fopen -> fopen_s

FILE *file = fopen(filename, "rb");

FILE *file;
fopen_s(&file,filename,"rw");

  // crt_fopen_s.c  
// This program opens two files. It uses  
// fclose to close the first file and  
// _fcloseall to close all remaining files.  
  
#include <stdio.h>  
  
FILE *stream, *stream2;  
  
int main( void )  
{  
   errno_t err;  
  
   // Open for read (will fail if file "crt_fopen_s.c" does not exist)  
   err  = fopen_s( &stream, "crt_fopen_s.c", "r" );  
   if( err == 0 )  
   {  
      printf( "The file 'crt_fopen_s.c' was opened\n" );  
   }  
   else  
   {  
      printf( "The file 'crt_fopen_s.c' was not opened\n" );  
   }  
  
   // Open for write   
   err = fopen_s( &stream2, "data2", "w+" );  
   if( err == 0 )  
   {  
      printf( "The file 'data2' was opened\n" );  
   }  
   else  
   {  
      printf( "The file 'data2' was not opened\n" );  
   }  
  
   // Close stream if it is not NULL   
   if( stream )  
   {  
      err = fclose( stream );  
      if ( err == 0 )  
      {  
         printf( "The file 'crt_fopen_s.c' was closed\n" );  
      }  
      else  
      {  
         printf( "The file 'crt_fopen_s.c' was not closed\n" );  
      }  
   }  
  
   // All other files are closed:  
   int numclosed = _fcloseall( );  
   printf( "Number of files closed by _fcloseall: %u\n", numclosed );  
}