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C6066

warning C6066: non-pointer passed as parameter <number> when pointer is required in call to <function>

This warning indicates that the format string specifies that a pointer is required, for example, a %n or %p specification for printf or a %d for scanf, but a non-pointer is being passed. This defect is likely to cause a crash or corruption of some form.

The following code generates this warning:

#include <stdio.h>
#define MAX 30
void f( )
{
  char buff[MAX];
  sprintf( buff, "%s %p %d", "Hello, World!", 1, MAX ); //warning C6066
  // code ...
}

void g( int i )
{
   int   result;
   result = scanf( "%d", i ); // warning C6066
   // code ...
}

To correct this warning, the following code passes correct parameters to the sprintf and scanf functions:

#include <stdio.h>
#define MAX 30

void f( )
{
   char buff[MAX];

   sprintf( buff, "%s %p %d", "Hello, World!", buff, MAX ); // pass buff
   // code ... 
}
void g( int i )
{
   int   result;
   // code ...
   result = scanf( "%d", &i ); // pass the address of i
   // code ...
}

The following code use safe string manipulation functions — sprintf_s and scanf_s — to correct this warning:

void f( )
{
   char buff[MAX];
  
   sprintf_s( buff, sizeof(buff), "%s %p %d", "Hello, World!", buff, MAX ); 
   // code ... 
}
void g( int i )
{
   int result;
   // code ...
   result = scanf_s( "%d", &i ); 
   // code ...
}

This warning is typically reported because an integer has been used for a %p format instead of a pointer. Using an integer in this instance is not portable to 64-bit computers.

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