RTM_IPV4_LEN_FROM_MASK macro (rtmv2.h)
The RTM_IPV4_LEN_FROM_MASK macro converts an IPv4 mask to a generic route length.
Syntax
void RTM_IPV4_LEN_FROM_MASK(
Len,
Mask
);
Parameters
Len
Receives the converted length
Mask
Specifies the mask to convert.
Return value
None
Remarks
For example, if a client supplies the Mask 255.255.255.255, the Len 24 is returned.
The macro is defined as follows:
#include <windows.h>
#define RTM_CHECK_NTH_BIT(Value, N, Len) \
if ((Value) & (1 << (N))) \
{ \
(Len) += (N); (Value) <<= (N); \
}
#define RTM_IPV4_LEN_FROM_MASK(Len, Mask) \
{ \
ULONG _Temp_ = ntohl(Mask); \
(Len) = 0; \
RTM_CHECK_NTH_BIT(_Temp_, 16, (Len)); \
RTM_CHECK_NTH_BIT(_Temp_, 8, (Len)); \
RTM_CHECK_NTH_BIT(_Temp_, 4, (Len)); \
while (_Temp_) \
{ \
(Len) += 1; _Temp_ <<= 1; \
} \
} \
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | None supported |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | rtmv2.h |