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Compiler Warning (level 4) C4816

Error Message

'param' : parameter has a zero-sized array which will be truncated (unless the object is passed by reference)

A parameter to an object with a zero-size array was not passed by reference. The array will not get copied when the object is passed.


The following sample generates C4816:

// C4816.cpp
// compile with: /W4
#include <stdio.h>

extern "C" int printf_s(const char *, ...);

#pragma warning(disable : 4200)

struct S1
    int i;
    char cArr[];

void TestErr(S1 s1)   // C4816 param with zero-array 
                      // not passed by reference
    printf_s("%d %c %c\n", s1.i, s1.cArr[0], s1.cArr[1]);

void TestOk(S1 &s1)
    printf_s("%d %c %c\n", s1.i, s1.cArr[0], s1.cArr[1]);

int main()
    S1 myS_1 = { 6, 'a', 'b', 'c' };