Change 'NULL' to 'null'

library/std/src/ffi/c_str.rs

@@ -498,7 +498,7 @@ impl CString {
     /// Failure to call [`CString::from_raw`] will lead to a memory leak.
     ///
     /// The C side must **not** modify the length of the string (by writing a
-    /// `NULL` somewhere inside the string or removing the final one) before
+    /// `null` somewhere inside the string or removing the final one) before
     /// it makes it back into Rust using [`CString::from_raw`]. See the safety section
     /// in [`CString::from_raw`].
     ///

library/std/src/sys/unix/ext/net/ancillary.rs

@@ -49,7 +49,7 @@ pub(super) fn recv_vectored_with_ancillary_from(
                 msg.msg_controllen = ancillary.buffer.len() as libc::socklen_t;
             }
         }
-        // macos requires that the control pointer is NULL when the len is 0.
+        // macos requires that the control pointer is null when the len is 0.
         if msg.msg_controllen > 0 {
             msg.msg_control = ancillary.buffer.as_mut_ptr().cast();
         }
@@ -97,7 +97,7 @@ pub(super) fn send_vectored_with_ancillary_to(
                 msg.msg_controllen = ancillary.length as libc::socklen_t;
             }
         }
-        // macos requires that the control pointer is NULL when the len is 0.
+        // macos requires that the control pointer is null when the len is 0.
         if msg.msg_controllen > 0 {
             msg.msg_control = ancillary.buffer.as_mut_ptr().cast();
         }

library/std/src/sys/unix/fs.rs

@@ -116,7 +116,7 @@ cfg_has_statx! {{
 
         match STATX_STATE.load(Ordering::Relaxed) {
             0 => {
-                // It is a trick to call `statx` with NULL pointers to check if the syscall
+                // It is a trick to call `statx` with null pointers to check if the syscall
                 // is available. According to the manual, it is expected to fail with EFAULT.
                 // We do this mainly for performance, since it is nearly hundreds times
                 // faster than a normal successful call.
@@ -450,7 +450,7 @@ impl Iterator for ReadDir {
                 super::os::set_errno(0);
                 let entry_ptr = libc::readdir(self.inner.dirp.0);
                 if entry_ptr.is_null() {
-                    // NULL can mean either the end is reached or an error occurred.
+                    // null can mean either the end is reached or an error occurred.
                     // So we had to clear errno beforehand to check for an error now.
                     return match super::os::errno() {
                         0 => None,

library/std/src/sys/unix/process/process_common.rs

@@ -153,7 +153,7 @@ impl Command {
     }
 
     pub fn arg(&mut self, arg: &OsStr) {
-        // Overwrite the trailing NULL pointer in `argv` and then add a new null
+        // Overwrite the trailing null pointer in `argv` and then add a new null
         // pointer.
         let arg = os2c(arg, &mut self.saw_nul);
         self.argv.0[self.args.len()] = arg.as_ptr();

library/std/src/thread/local.rs

@@ -722,7 +722,7 @@ pub mod os {
     unsafe extern "C" fn destroy_value<T: 'static>(ptr: *mut u8) {
         // SAFETY:
         //
-        // The OS TLS ensures that this key contains a NULL value when this
+        // The OS TLS ensures that this key contains a null value when this
         // destructor starts to run. We set it back to a sentinel value of 1 to
         // ensure that any future calls to `get` for this thread will return
         // `None`.