static extern bool Process32First([In]IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

        if (Process32First(handleToSnapshot, ref procEntry))

PROCESSENTRY32, Process32First, Process32Next

static extern bool Process32First(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

Private Shared Function Process32First(ByVal hSnapshot As IntPtr, ByRef lppe As PROCESSENTRY32) As Boolean

Possibly you need to use this definition if Process32First fails with error code 87 (invalid argument)