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.

Example

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.

See Also

sprintf_s, _sprintf_s_l, swprintf_s, _swprintf_s_l
scanf_s, _scanf_s_l, wscanf_s, _wscanf_s_l