Function len [src]

Takes a sentinel-terminated pointer and iterates over the memory to find the sentinel and determine the length. [*c] pointers are assumed to be non-null and 0-terminated.

Prototype

pub fn len(value: anytype) usize

Example

 test len {
    var array: [5]u16 = [_]u16{ 1, 2, 0, 4, 5 };
    const ptr = @as([*:4]u16, array[0..3 :4]);
    try testing.expect(len(ptr) == 3);
    const c_ptr = @as([*c]u16, ptr);
    try testing.expect(len(c_ptr) == 2);
}

Source

  pub fn len(value: anytype) usize {
    switch (@typeInfo(@TypeOf(value))) {
        .pointer => |info| switch (info.size) {
            .many => {
                const sentinel = info.sentinel() orelse
                    @compileError("invalid type given to std.mem.len: " ++ @typeName(@TypeOf(value)));
                return indexOfSentinel(info.child, sentinel, value);
            },
            .c => {
                assert(value != null);
                return indexOfSentinel(info.child, 0, value);
            },
            else => @compileError("invalid type given to std.mem.len: " ++ @typeName(@TypeOf(value))),
        },
        else => @compileError("invalid type given to std.mem.len: " ++ @typeName(@TypeOf(value))),
    }
}  