Rollup merge of #97336 - tshepang:typo, r=cjgillot

[rust.git] / library / std / src / f64.rs

diff --git a/library/std/src/f64.rs b/library/std/src/f64.rs
index 01279f01b0568caa8601f720b137b8fef866604f..a9aa84f70d19e08fcc4341a2a52ffb984afe43d4 100644 (file)
--- a/library/std/src/f64.rs
+++ b/library/std/src/f64.rs
@@ -29,7 +29,7 @@
 
 #[cfg(not(test))]
 impl f64 {
-    /// Returns the largest integer less than or equal to a number.
+    /// Returns the largest integer less than or equal to `self`.
     ///
     /// # Examples
     ///
@@ -50,7 +50,7 @@ pub fn floor(self) -> f64 {
         unsafe { intrinsics::floorf64(self) }
     }
 
-    /// Returns the smallest integer greater than or equal to a number.
+    /// Returns the smallest integer greater than or equal to `self`.
     ///
     /// # Examples
     ///
@@ -69,7 +69,7 @@ pub fn ceil(self) -> f64 {
         unsafe { intrinsics::ceilf64(self) }
     }
 
-    /// Returns the nearest integer to a number. Round half-way cases away from
+    /// Returns the nearest integer to `self`. Round half-way cases away from
     /// `0.0`.
     ///
     /// # Examples
@@ -89,7 +89,8 @@ pub fn round(self) -> f64 {
         unsafe { intrinsics::roundf64(self) }
     }
 
-    /// Returns the integer part of a number.
+    /// Returns the integer part of `self`.
+    /// This means that non-integer numbers are always truncated towards zero.
     ///
     /// # Examples
     ///
@@ -110,7 +111,7 @@ pub fn trunc(self) -> f64 {
         unsafe { intrinsics::truncf64(self) }
     }
 
-    /// Returns the fractional part of a number.
+    /// Returns the fractional part of `self`.
     ///
     /// # Examples
     ///
@@ -131,8 +132,7 @@ pub fn fract(self) -> f64 {
         self - self.trunc()
     }
 
-    /// Computes the absolute value of `self`. Returns `NAN` if the
-    /// number is `NAN`.
+    /// Computes the absolute value of `self`.
     ///
     /// # Examples
     ///
@@ -160,7 +160,7 @@ pub fn abs(self) -> f64 {
     ///
     /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
     /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
-    /// - `NAN` if the number is `NAN`
+    /// - NaN if the number is NaN
     ///
     /// # Examples
     ///
@@ -184,8 +184,10 @@ pub fn signum(self) -> f64 {
     /// `sign`.
     ///
     /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise
-    /// equal to `-self`. If `self` is a `NAN`, then a `NAN` with the sign of
-    /// `sign` is returned.
+    /// equal to `-self`. If `self` is a NaN, then a NaN with the sign bit of
+    /// `sign` is returned. Note, however, that conserving the sign bit on NaN
+    /// across arithmetical operations is not generally guaranteed.
+    /// See [explanation of NaN as a special value](primitive@f32) for more info.
     ///
     /// # Examples
     ///
@@ -298,7 +300,9 @@ pub fn rem_euclid(self, rhs: f64) -> f64 {
 
     /// Raises a number to an integer power.
     ///
-    /// Using this function is generally faster than using `powf`
+    /// Using this function is generally faster than using `powf`.
+    /// It might have a different sequence of rounding operations than `powf`,
+    /// so the results are not guaranteed to agree.
     ///
     /// # Examples
     ///
@@ -513,15 +517,15 @@ pub fn log10(self) -> f64 {
     #[must_use = "method returns a new number and does not mutate the original value"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
-    #[rustc_deprecated(
+    #[deprecated(
         since = "1.10.0",
-        reason = "you probably meant `(self - other).abs()`: \
-                  this operation is `(self - other).max(0.0)` \
-                  except that `abs_sub` also propagates NaNs (also \
-                  known as `fdim` in C). If you truly need the positive \
-                  difference, consider using that expression or the C function \
-                  `fdim`, depending on how you wish to handle NaN (please consider \
-                  filing an issue describing your use-case too)."
+        note = "you probably meant `(self - other).abs()`: \
+                this operation is `(self - other).max(0.0)` \
+                except that `abs_sub` also propagates NaNs (also \
+                known as `fdim` in C). If you truly need the positive \
+                difference, consider using that expression or the C function \
+                `fdim`, depending on how you wish to handle NaN (please consider \
+                filing an issue describing your use-case too)."
     )]
     pub fn abs_sub(self, other: f64) -> f64 {
         unsafe { cmath::fdim(self, other) }