Compiler Error C3488
'var' is not allowed when the default capture mode is by-reference
When you specify that the default capture mode for a lambda expression is by-reference, you cannot pass a variable by reference to the capture clause of that expression.
To correct this error
Do not explicitly pass the variable to the capture clause, or
Do not specify by-reference as the default capture mode, or
Specify by-value as the default capture mode, or
Pass the variable by value to the capture clause. (This might change the behavior of the lambda expression.)
Examples
The following example generates C3488 because a reference to the variable n appears in the capture clause of a lambda expression whose default mode is by-reference:
// C3488a.cpp
int main()
{
int n = 5;
[&, &n]() { return n; } (); // C3488
}
The following example shows four possible resolutions to C3488:
// C3488b.cpp
int main()
{
int n = 5;
// Possible resolution 1:
// Do not explicitly pass &n to the capture clause.
[&]() { return n; } ();
// Possible resolution 2:
// Do not specify by-reference as the default capture mode.
[&n]() { return n; } ();
// Possible resolution 3:
// Specify by-value as the default capture mode.
[=, &n]() { return n; } ();
// Possible resolution 4:
// Pass n by value to the capture clause.
[n]() { return n; } ();
}