compiler-warning-level-4-c4703.md

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Learn more about: Compiler Warning (level 4) C4703	Compiler Warning (level 4) C4703	08/30/2022	C4703	C4703	5dad454e-69e3-4931-9168-050a861c05f8

Compiler Warning (level 4) C4703

Potentially uninitialized local pointer variable 'name' used

Remarks

The local pointer variable name might have been used without being assigned a value. This access could lead to unpredictable results.

The /sdl (Enable Additional Security Checks) compiler option elevates this warning to an error.

Example

The following code generates C4701 and C4703.

#include <malloc.h>

void func(int size)
{
    void* p;
    if (size < 256) {
        p = malloc(size);
    }

    if (p != nullptr) // C4701 and C4703
        free(p);
}

int main()
{
    func(9);
}

c:\src\test.cpp(10) : warning C4701: potentially uninitialized local variable 'p' used
c:\src\test.cpp(10) : warning C4703: potentially uninitialized local pointer variable 'p' used

To correct this warning, initialize the variable as shown in this example:

#include <malloc.h>

void func(int size)
{
    void* p = nullptr;
    if (size < 256) {
        p = malloc(size);
    }

    if (p != nullptr)
        free(p);
}

int main()
{
    func(9);
}

See also

Compiler Warning (level 4) C4701
Warnings, /sdl, and improving uninitialized variable detection