Warning C6001
Using uninitialized memory 'variable'.
Remarks
This warning is reported when an uninitialized local variable is used before it's assigned a value. This usage could lead to unpredictable results. You should always initialize variables before use.
Code analysis name: USING_UNINIT_VAR
Example
The following code generates this warning because variable i is only initialized if b is true:
int f( bool b )
{
int i;
if ( b )
{
i = 0;
}
return i; // i is uninitialized if b is false
}
To correct this warning, initialize the variable as shown in the following code:
int f( bool b )
{
int i = -1;
if ( b )
{
i = 0;
}
return i;
}
Heuristics
The following example shows that passing a variable to a function by reference causes the compiler to assume that it's initialized:
void init( int& i );
int f( bool b )
{
int i;
init(i);
if ( b )
{
i = 0;
}
return i; // i is assumed to be initialized because it's passed by reference to init()
}
This supports the pattern of passing a pointer to a variable into an initialization function.
This heuristic can lead to false negatives because many functions expect pointers that point to initialized data. Use SAL annotations, such as _In_ and _Out_, to describe the function's behavior. The following example calls a function that expects its argument to be initialized, so a warning is generated:
void use( _In_ int& i );
int f( bool b )
{
int i;
use(i); // uninitialized variable warning because of the _In_ annotation on use()
if ( b )
{
i = 0;
}
return i;
}