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--- Libc/Libc-262/stdlib/qsort.3
+++ Libc/Libc-763.11/stdlib/qsort.3
@@ -13,10 +13,6 @@
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
@@ -34,24 +30,84 @@
.\" SUCH DAMAGE.
.\"
.\" @(#)qsort.3 8.1 (Berkeley) 6/4/93
-.\" $FreeBSD: src/lib/libc/stdlib/qsort.3,v 1.10 2001/09/07 14:46:35 asmodai Exp $
-.\"
-.Dd June 4, 1993
+.\" $FreeBSD: src/lib/libc/stdlib/qsort.3,v 1.17 2007/01/09 00:28:10 imp Exp $
+.\"
+.Dd September 30, 2003
.Dt QSORT 3
.Os
.Sh NAME
-.Nm qsort , heapsort , mergesort
+.Nm heapsort ,
+#ifdef UNIFDEF_BLOCKS
+.Nm heapsort_b ,
+#endif
+.Nm mergesort ,
+#ifdef UNIFDEF_BLOCKS
+.Nm mergesort_b ,
+#endif
+.Nm qsort ,
+#ifdef UNIFDEF_BLOCKS
+.Nm qsort_b ,
+#endif
+.Nm qsort_r
.Nd sort functions
-.Sh LIBRARY
-.Lb libc
.Sh SYNOPSIS
.In stdlib.h
+.Ft int
+.Fo heapsort
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#ifdef UNIFDEF_BLOCKS
+.Ft int
+.Fo heapsort_b
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]^compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#endif
+.Ft int
+.Fo mergesort
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#ifdef UNIFDEF_BLOCKS
+.Ft int
+.Fo mergesort_b
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]^compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#endif
.Ft void
-.Fn qsort "void *base" "size_t nmemb" "size_t size" "int (*compar)(const void *, const void *)"
-.Ft int
-.Fn heapsort "void *base" "size_t nmemb" "size_t size" "int (*compar)(const void *, const void *)"
-.Ft int
-.Fn mergesort "void *base" "size_t nmemb" "size_t size" "int (*compar)(const void *, const void *)"
+.Fo qsort
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]*compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#ifdef UNIFDEF_BLOCKS
+.Ft void
+.Fo qsort_b
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "int \*[lp]^compar\*[rp]\*[lp]const void *, const void *\*[rp]"
+.Fc
+#endif
+.Ft void
+.Fo qsort_r
+.Fa "void *base"
+.Fa "size_t nel"
+.Fa "size_t width"
+.Fa "void *thunk"
+.Fa "int \*[lp]*compar\*[rp]\*[lp]void *, const void *, const void *\*[rp]"
+.Fc
.Sh DESCRIPTION
The
.Fn qsort
@@ -61,7 +117,7 @@
function is a modified selection sort.
The
.Fn mergesort
-function is a modified merge sort with exponential search
+function is a modified merge sort with exponential search,
intended for sorting data with pre-existing order.
.Pp
The
@@ -69,17 +125,19 @@
and
.Fn heapsort
functions sort an array of
-.Fa nmemb
+.Fa nel
objects, the initial member of which is pointed to by
.Fa base .
The size of each object is specified by
-.Fa size .
-.Fn Mergesort
+.Fa width .
+The
+.Fn mergesort
+function
behaves similarly, but
.Em requires
that
-.Fa size
-be greater than
+.Fa width
+be greater than or equal to
.Dq "sizeof(void *) / 2" .
.Pp
The contents of the array
@@ -94,33 +152,58 @@
greater than zero if the first argument is considered to be respectively
less than, equal to, or greater than the second.
.Pp
-The functions
-.Fn qsort
+The
+.Fn qsort_r
+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
+.Fa compar .
+This allows the comparison function to access additional
+data without using global variables, and thus
+.Fn qsort_r
+is suitable for use in functions which must be reentrant.
+.Pp
+The algorithms implemented by
+.Fn qsort ,
+.Fn qsort_r ,
and
.Fn heapsort
are
.Em not
-stable, that is, if two members compare as equal, their order in
+stable; that is, if two members compare as equal, their order in
the sorted array is undefined.
-The function
-.Fn mergesort
-is stable.
-.Pp
-The
-.Fn qsort
-function is an implementation of C.A.R. Hoare's ``quicksort'' algorithm,
-a variant of partition-exchange sorting; in particular, see D.E. Knuth's
-Algorithm Q.
-.Fn Qsort
+The
+.Fn mergesort
+algorithm is stable.
+.Pp
+The
+.Fn qsort
+and
+.Fn qsort_r
+functions are an implementation of C.A.R.
+Hoare's
+.Dq quicksort
+algorithm,
+a variant of partition-exchange sorting; in particular, see
+.An D.E. Knuth Ns 's
+.%T "Algorithm Q" .
+.Sy Quicksort
takes O N lg N average time.
This implementation uses median selection to avoid its
O N**2 worst-case behavior.
.Pp
The
.Fn heapsort
-function is an implementation of J.W.J. William's ``heapsort'' algorithm,
-a variant of selection sorting; in particular, see D.E. Knuth's Algorithm H.
-.Fn Heapsort
+function is an implementation of
+.An "J.W.J. William" Ns 's
+.Dq heapsort
+algorithm,
+a variant of selection sorting; in particular, see
+.An "D.E. Knuth" Ns 's
+.%T "Algorithm H" .
+.Sy Heapsort
takes O N lg N worst-case time.
Its
.Em only
@@ -133,10 +216,12 @@
The function
.Fn mergesort
requires additional memory of size
-.Fa nmemb *
-.Fa size
+.Fa nel *
+.Fa width
bytes; it should be used only when space is not at a premium.
-.Fn Mergesort
+The
+.Fn mergesort
+function
is optimized for data with pre-existing order; its worst case
time is O N lg N; its best case is O N.
.Pp
@@ -144,46 +229,91 @@
.Fn qsort
is faster than
.Fn mergesort
-is faster than
+which is faster than
.Fn heapsort .
Memory availability and pre-existing order in the data can make this
untrue.
+#ifdef UNIFDEF_BLOCKS
+.Pp
+The
+.Fn heapsort_b ,
+.Fn mergesort_b ,
+and
+.Fn qsort_b
+routines are like the corresponding routines without the _b suffix, expect
+that the
+.Fa compar
+callback is a block pointer instead of a function pointer.
+#endif
.Sh RETURN VALUES
The
-.Fn qsort
-function
-returns no value.
-.Pp
-.Rv -std heapsort mergesort
+#ifdef UNIFDEF_BLOCKS
+.Fn qsort ,
+.Fn qsort_b
+#else
+.Fn qsort
+#endif
+and
+.Fn qsort_r
+functions
+return no value.
+.Pp
+#ifdef UNIFDEF_BLOCKS
+.ds HEAPSORT_B heapsort_b
+.ds MERGESORT_B mergesort_b
+#endif
+.Rv -std heapsort \*[HEAPSORT_B] mergesort \*[MERGESORT_B]
+.Sh COMPATIBILITY
+Previous versions of
+.Fn qsort
+did not permit the comparison routine itself to call
+.Fn qsort 3 .
+This is no longer true.
.Sh ERRORS
The
-.Fn heapsort
-and
-.Fn mergesort
+#ifdef UNIFDEF_BLOCKS
+.Fn heapsort ,
+.Fn heapsort_b ,
+.Fn mergesort ,
+and
+.Fn mergesort_b
+#else
+.Fn heapsort
+and
+.Fn mergesort
+#endif
functions succeed unless:
.Bl -tag -width Er
.It Bq Er EINVAL
The
-.Fa size
+.Fa width
argument is zero, or,
the
-.Fa size
+.Fa width
argument to
.Fn mergesort
+#ifdef UNIFDEF_BLOCKS
+or
+.Fn mergesort_b
+#endif
is less than
.Dq "sizeof(void *) / 2" .
.It Bq Er ENOMEM
-.Fn Heapsort
+The
+#ifdef UNIFDEF_BLOCKS
+.Fn heapsort ,
+.Fn heapsort_b ,
+.Fn mergesort ,
or
-.Fn mergesort
+.Fn mergesort_b
+#else
+.Fn heapsort
+or
+.Fn mergesort
+#endif
+functions
were unable to allocate memory.
.El
-.Sh COMPATIBILITY
-Previous versions of
-.Fn qsort
-did not permit the comparison routine itself to call
-.Fn qsort 3 .
-This is no longer true.
.Sh SEE ALSO
.Xr sort 1 ,
.Xr radixsort 3
@@ -212,16 +342,19 @@
.%P pp. 114-123, 145-149
.Re
.Rs
-.%A Mcilroy, P.M.
+.%A McIlroy, P.M.
.%T "Optimistic Sorting and Information Theoretic Complexity"
.%J "Fourth Annual ACM-SIAM Symposium on Discrete Algorithms"
.%V January 1992
.Re
.Rs
.%A Bentley, J.L.
+.%A McIlroy, M.D.
.%T "Engineering a Sort Function"
-.%J "bentley@research.att.com"
-.%V January 1992
+.%J "Software--Practice and Experience"
+.%V Vol. 23(11)
+.%P pp. 1249-1265
+.%D November\ 1993
.Re
.Sh STANDARDS
The