1 files changed, 36 insertions, 28 deletions
diff --git a/lib/libc/stdlib/qsort.3 b/lib/libc/stdlib/qsort.3
index 606185f9baee..e2e29e7cf04f 100644
--- a/lib/libc/stdlib/qsort.3
+++ b/lib/libc/stdlib/qsort.3
@@ -29,10 +29,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"     @(#)qsort.3	8.1 (Berkeley) 6/4/93
-.\" $FreeBSD$
-.\"
-.Dd January 20, 2020
+.Dd October 25, 2024
 .Dt QSORT 3
 .Os
 .Sh NAME
@@ -67,8 +64,8 @@
 .Fa "void *base"
 .Fa "size_t nmemb"
 .Fa "size_t size"
+.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *, void *\*[rp]"
 .Fa "void *thunk"
-.Fa "int \*[lp]*compar\*[rp]\*[lp]void *, const void *, const void *\*[rp]"
 .Fc
 .Ft int
 .Fo heapsort
@@ -157,7 +154,7 @@ function behaves identically to
 .Fn qsort ,
 except that it takes an additional argument,
 .Fa thunk ,
-which is passed unchanged as the first argument to function pointed to
+which is passed unchanged as the last argument to function pointed to
 .Fa compar .
 This allows the comparison function to access additional
 data without using global variables, and thus
@@ -251,16 +248,8 @@ untrue.
 The
 .Fn qsort_s
 function behaves the same as
-.Fn qsort_r , except that:
-.Bl -dash
-.It
-The order of arguments is different
-.It
-The order of arguments to
-.Fa compar
-is different
-.It
-if
+.Fn qsort_r ,
+except that if
 .Fa nmemb
 or
 .Fa size
@@ -270,13 +259,16 @@ or
 .Fa nmemb
 is not zero and
 .Fa compar
-is NULL, then the runtime-constraint handler is called, and
+is
+.Dv NULL
+or
+.Fa size
+is zero, then the runtime-constraint handler is called, and
 .Fn qsort_s
 returns an error.
 Note that the handler is called before
 .Fn qsort_s
 returns the error, and the handler function might not return.
-.El
 .Sh RETURN VALUES
 The
 .Fn qsort
@@ -332,16 +324,21 @@ main(void)
 .Sh COMPATIBILITY
 The order of arguments for the comparison function used with
 .Fn qsort_r
-is different from the one used by
-.Fn qsort_s ,
+is historically different from the one used by
+.Fn qsort_s
 and the GNU libc implementation of
 .Fn qsort_r .
-When porting software written for GNU libc, it is usually possible
-to replace
+However, as of
+.Fx 14.0 ,
+the
 .Fn qsort_r
-with
-.Fn qsort_s
-to work around this problem.
+has been updated so that the
+.Fa thunk
+parameter appears last to match
+.St -p1003.1-2024 .
+Both the historical and the updated interfaces are now accepted
+via C11 generic selection and C++ polymorphism,
+but the updated interface is recommended for portable applications.
 .Pp
 .Fn qsort_s
 is part of the
@@ -425,14 +422,25 @@ were unable to allocate memory.
 .Sh STANDARDS
 The
 .Fn qsort
-function
-conforms to
+function conforms to
 .St -isoC .
+The
+.Fn qsort_r
+function conforms to
+.St -p1003.1-2024 .
+The
 .Fn qsort_s
-conforms to
+function conforms to
 .St -isoC-2011
 K.3.6.3.2.
 .Sh HISTORY
 The variants of these functions that take blocks as arguments first appeared in
 Mac OS X.
 This implementation was created by David Chisnall.
+.Pp
+In
+.Fx 14.0 ,
+the prototype of
+.Fn qsort_r
+was updated to match
+.St -p1003.1-2024 .