diff --git a/doc/langref.html.in b/doc/langref.html.in index 0da6d60257..5a46107d2a 100644 --- a/doc/langref.html.in +++ b/doc/langref.html.in @@ -2671,6 +2671,36 @@ test "pointer array access" { try expect(array[2] == 3); ptr.* += 1; try expect(array[2] == 4); +} + {#code_end#} +
+ Zig supports pointer arithmetic. It's better to assign the pointer to {#syntax#}[*]T{#endsyntax#} and increment that variable. For example, directly incrementing the pointer from a slice will corrupt it. +
+ {#code_begin|test|pointer_arthemtic#} +const expect = @import("std").testing.expect; + +test "pointer arithmetic with many-item pointer" { + const array = [_]i32{ 1, 2, 3, 4 }; + var ptr: [*]const i32 = &array; + + try expect(ptr[0] == 1); + ptr += 1; + try expect(ptr[0] == 2); +} + +test "pointer arithmetic with slices" { + var array = [_]i32{ 1, 2, 3, 4 }; + var length: usize = 0; + var slice = array[length..array.len]; + + try expect(slice[0] == 1); + try expect(slice.len == 4); + + slice.ptr += 1; + // now the slice is in an bad state since len has not been updated + + try expect(slice[0] == 2); + try expect(slice.len == 4); } {#code_end#}