Add lint unsafe_sizeof_count_copies

CHANGELOG.md

@@ -2124,6 +2124,7 @@ Released 2018-09-13
 [`unreadable_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#unreadable_literal
 [`unsafe_derive_deserialize`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_derive_deserialize
 [`unsafe_removed_from_name`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_removed_from_name
+[`unsafe_sizeof_count_copies`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_sizeof_count_copies
 [`unsafe_vector_initialization`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_vector_initialization
 [`unseparated_literal_suffix`]: https://rust-lang.github.io/rust-clippy/master/index.html#unseparated_literal_suffix
 [`unsound_collection_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsound_collection_transmute

clippy_lints/src/lib.rs

@@ -329,6 +329,7 @@ macro_rules! declare_clippy_lint {
 mod unnecessary_wraps;
 mod unnested_or_patterns;
 mod unsafe_removed_from_name;
+mod unsafe_sizeof_count_copies;
 mod unused_io_amount;
 mod unused_self;
 mod unused_unit;
@@ -916,6 +917,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &unnecessary_wraps::UNNECESSARY_WRAPS,
         &unnested_or_patterns::UNNESTED_OR_PATTERNS,
         &unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME,
+        &unsafe_sizeof_count_copies::UNSAFE_SIZEOF_COUNT_COPIES,
         &unused_io_amount::UNUSED_IO_AMOUNT,
         &unused_self::UNUSED_SELF,
         &unused_unit::UNUSED_UNIT,
@@ -998,6 +1000,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(move || box matches::Matches::new(msrv));
     store.register_early_pass(move || box manual_non_exhaustive::ManualNonExhaustive::new(msrv));
     store.register_late_pass(move || box manual_strip::ManualStrip::new(msrv));
+    store.register_late_pass(|| box unsafe_sizeof_count_copies::UnsafeSizeofCountCopies);
     store.register_late_pass(|| box map_clone::MapClone);
     store.register_late_pass(|| box map_err_ignore::MapErrIgnore);
     store.register_late_pass(|| box shadow::Shadow);
@@ -1605,6 +1608,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&unnecessary_sort_by::UNNECESSARY_SORT_BY),
         LintId::of(&unnecessary_wraps::UNNECESSARY_WRAPS),
         LintId::of(&unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME),
+        LintId::of(&unsafe_sizeof_count_copies::UNSAFE_SIZEOF_COUNT_COPIES),
         LintId::of(&unused_io_amount::UNUSED_IO_AMOUNT),
         LintId::of(&unused_unit::UNUSED_UNIT),
         LintId::of(&unwrap::PANICKING_UNWRAP),
@@ -1883,6 +1887,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&unit_return_expecting_ord::UNIT_RETURN_EXPECTING_ORD),
         LintId::of(&unnamed_address::FN_ADDRESS_COMPARISONS),
         LintId::of(&unnamed_address::VTABLE_ADDRESS_COMPARISONS),
+        LintId::of(&unsafe_sizeof_count_copies::UNSAFE_SIZEOF_COUNT_COPIES),
         LintId::of(&unused_io_amount::UNUSED_IO_AMOUNT),
         LintId::of(&unwrap::PANICKING_UNWRAP),
         LintId::of(&vec_resize_to_zero::VEC_RESIZE_TO_ZERO),

clippy_lints/src/unsafe_sizeof_count_copies.rs

@@ -0,0 +1,98 @@
+//! Lint on unsafe memory copying that use the `size_of` of the pointee type instead of a pointee
+//! count
+
+use crate::utils::{match_def_path, paths, span_lint_and_help};
+use if_chain::if_chain;
+use rustc_hir::BinOpKind;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{Ty as TyM, TyS};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// **What it does:** Detects expressions where
+    /// size_of::<T> is used as the count argument to unsafe
+    /// memory copying functions like ptr::copy and
+    /// ptr::copy_nonoverlapping where T is the pointee type
+    /// of the pointers used
+    ///
+    /// **Why is this bad?** These functions expect a count
+    /// of T and not a number of bytes, which can lead to
+    /// copying the incorrect amount of bytes, which can
+    /// result in Undefined Behaviour
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust,no_run
+    /// # use std::ptr::copy_nonoverlapping;
+    /// # use std::mem::size_of;
+    ///
+    /// const SIZE: usize = 128;
+    /// let x = [2u8; SIZE];
+    /// let mut y = [2u8; SIZE];
+    /// unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    /// ```
+    pub UNSAFE_SIZEOF_COUNT_COPIES,
+    correctness,
+    "unsafe memory copying using a byte count instead of a count of T"
+}
+
+declare_lint_pass!(UnsafeSizeofCountCopies => [UNSAFE_SIZEOF_COUNT_COPIES]);
+
+fn get_size_of_ty(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<TyM<'tcx>> {
+    match &expr.kind {
+        ExprKind::Call(ref count_func, _func_args) => {
+            if_chain! {
+                if let ExprKind::Path(ref count_func_qpath) = count_func.kind;
+                if let Some(def_id) = cx.qpath_res(count_func_qpath, count_func.hir_id).opt_def_id();
+                if match_def_path(cx, def_id, &paths::MEM_SIZE_OF)
+                    || match_def_path(cx, def_id, &paths::MEM_SIZE_OF_VAL);
+                then {
+                    cx.typeck_results().node_substs(count_func.hir_id).types().next()
+                } else {
+                    None
+                }
+            }
+        },
+        ExprKind::Binary(op, left, right) if BinOpKind::Mul == op.node || BinOpKind::Div == op.node => {
+            get_size_of_ty(cx, &*left).or_else(|| get_size_of_ty(cx, &*right))
+        },
+        _ => None,
+    }
+}
+
+impl<'tcx> LateLintPass<'tcx> for UnsafeSizeofCountCopies {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if_chain! {
+            // Find calls to ptr::copy and copy_nonoverlapping
+            if let ExprKind::Call(ref func, ref func_args) = expr.kind;
+            if let ExprKind::Path(ref func_qpath) = func.kind;
+            if let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id();
+            if match_def_path(cx, def_id, &paths::COPY_NONOVERLAPPING)
+                || match_def_path(cx, def_id, &paths::COPY);
+
+            // Get the pointee type
+            let _substs = cx.typeck_results().node_substs(func.hir_id);
+            if let Some(pointee_ty) = cx.typeck_results().node_substs(func.hir_id).types().next();
+
+            // Find a size_of call in the count parameter expression and
+            // check that it's the same type
+            if let [_src, _dest, count] = &**func_args;
+            if let Some(ty_used_for_size_of) = get_size_of_ty(cx, count);
+            if TyS::same_type(pointee_ty, ty_used_for_size_of);
+            then {
+                span_lint_and_help(
+                    cx,
+                    UNSAFE_SIZEOF_COUNT_COPIES,
+                    expr.span,
+                    "unsafe memory copying using a byte count (Multiplied by size_of::<T>) \
+                    instead of a count of T",
+                    None,
+                    "use a count of elements instead of a count of bytes for the count parameter, \
+                    it already gets multiplied by the size of the pointed to type"
+                );
+            }
+        };
+    }
+}

clippy_lints/src/utils/paths.rs

@@ -20,6 +20,8 @@
 pub const CLONE_TRAIT_METHOD: [&str; 4] = ["core", "clone", "Clone", "clone"];
 pub const CMP_MAX: [&str; 3] = ["core", "cmp", "max"];
 pub const CMP_MIN: [&str; 3] = ["core", "cmp", "min"];
+pub const COPY: [&str; 3] = ["core", "intrinsics", "copy_nonoverlapping"];
+pub const COPY_NONOVERLAPPING: [&str; 3] = ["core", "intrinsics", "copy"];
 pub const COW: [&str; 3] = ["alloc", "borrow", "Cow"];
 pub const CSTRING_AS_C_STR: [&str; 5] = ["std", "ffi", "c_str", "CString", "as_c_str"];
 pub const DEFAULT_TRAIT: [&str; 3] = ["core", "default", "Default"];
@@ -73,6 +75,8 @@
 pub const MEM_MAYBEUNINIT: [&str; 4] = ["core", "mem", "maybe_uninit", "MaybeUninit"];
 pub const MEM_MAYBEUNINIT_UNINIT: [&str; 5] = ["core", "mem", "maybe_uninit", "MaybeUninit", "uninit"];
 pub const MEM_REPLACE: [&str; 3] = ["core", "mem", "replace"];
+pub const MEM_SIZE_OF: [&str; 3] = ["core", "mem", "size_of"];
+pub const MEM_SIZE_OF_VAL: [&str; 3] = ["core", "mem", "size_of_val"];
 pub const MUTEX_GUARD: [&str; 4] = ["std", "sync", "mutex", "MutexGuard"];
 pub const OPEN_OPTIONS: [&str; 3] = ["std", "fs", "OpenOptions"];
 pub const OPS_MODULE: [&str; 2] = ["core", "ops"];

tests/ui/unsafe_sizeof_count_copies.rs

@@ -0,0 +1,54 @@
+#![warn(clippy::unsafe_sizeof_count_copies)]
+
+use std::mem::{size_of, size_of_val};
+use std::ptr::{copy, copy_nonoverlapping};
+
+fn main() {
+    const SIZE: usize = 128;
+    const HALF_SIZE: usize = SIZE / 2;
+    const DOUBLE_SIZE: usize = SIZE * 2;
+    let mut x = [2u8; SIZE];
+    let mut y = [2u8; SIZE];
+
+    // Count is size_of (Should trigger the lint)
+    unsafe { copy_nonoverlapping::<u8>(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
+
+    // Count expression involving multiplication of size_of (Should trigger the lint)
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * SIZE) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * SIZE) };
+
+    // Count expression involving nested multiplications of size_of (Should trigger the lint)
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * HALF_SIZE * 2) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE * HALF_SIZE) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * HALF_SIZE * 2) };
+
+    // Count expression involving divisions of size_of (Should trigger the lint)
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * DOUBLE_SIZE / 2) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / 2 * size_of_val(&x[0])) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u8>() / 2) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * DOUBLE_SIZE / 2) };
+
+    // No size_of calls (Should not trigger the lint)
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), SIZE) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), SIZE) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), SIZE) };
+
+    // Different types for pointee and size_of (Should not trigger the lint)
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>() / 2 * SIZE) };
+    unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&0u16) / 2 * SIZE) };
+
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u16>() / 2 * SIZE) };
+    unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&0u16) / 2 * SIZE) };
+}

tests/ui/unsafe_sizeof_count_copies.stderr

@@ -0,0 +1,131 @@
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:14:14
+   |
+LL |     unsafe { copy_nonoverlapping::<u8>(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::unsafe-sizeof-count-copies` implied by `-D warnings`
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:15:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:17:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>()) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:18:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0])) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:21:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:22:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * SIZE) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:24:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:25:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * SIZE) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:28:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * HALF_SIZE * 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:29:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), HALF_SIZE * size_of_val(&x[0]) * 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:31:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * SIZE * HALF_SIZE) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:32:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * HALF_SIZE * 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:35:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), size_of::<u8>() * DOUBLE_SIZE / 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:36:14
+   |
+LL |     unsafe { copy_nonoverlapping(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE / 2 * size_of_val(&x[0])) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:38:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), DOUBLE_SIZE * size_of::<u8>() / 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: unsafe memory copying using a byte count (Multiplied by size_of::<T>) instead of a count of T
+  --> $DIR/unsafe_sizeof_count_copies.rs:39:14
+   |
+LL |     unsafe { copy(x.as_ptr(), y.as_mut_ptr(), size_of_val(&x[0]) * DOUBLE_SIZE / 2) };
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use a count of elements instead of a count of bytes for the count parameter, it already gets multiplied by the size of the pointed to type
+
+error: aborting due to 16 previous errors
+