python · vstinner · Oct 15, 2021 · Oct 15, 2021
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
@@ -461,7 +461,8 @@ Build Changes
   (Contributed by Mike Gilbert in :issue:`45433`.)
 
 * Building Python now requires a C99 ``<math.h>`` header file providing
-  ``isinf()``, ``isnan()`` and ``isfinite()`` functions.
+  the following functions: ``copysign()``, ``hypot()``, ``isfinite()``,
+  ``isinf()``, ``isnan()``, ``round()``.
   (Contributed by Victor Stinner in :issue:`45440`.)
 
 C API Changes

diff --git a/Include/internal/pycore_pymath.h b/Include/internal/pycore_pymath.h
@@ -8,24 +8,6 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
-
-// Python provides implementations for copysign(), round() and hypot() in
-// Python/pymath.c just in case your math library doesn't provide the
-// functions.
-//
-// Note: PC/pyconfig.h defines copysign as _copysign
-#ifndef HAVE_COPYSIGN
-extern double copysign(double, double);
-#endif
-
-#ifndef HAVE_ROUND
-extern double round(double);
-#endif
-
-#ifndef HAVE_HYPOT
-extern double hypot(double, double);
-#endif
-
 // Extra declarations
 #if !defined(_MSC_VER) && !defined(__STDC__)
 extern double fmod (double, double);

diff --git a/Misc/NEWS.d/next/Build/2021-10-12-02-13-08.bpo-45440.-zYgDb.rst b/Misc/NEWS.d/next/Build/2021-10-12-02-13-08.bpo-45440.-zYgDb.rst
@@ -1,2 +1,4 @@
 Building Python now requires a C99 ``<math.h>`` header file providing
-``isinf()``, ``isnan()`` and ``isfinite()`` functions. Patch by Victor Stinner.
+the following functions: ``copysign()``, ``hypot()``, ``isfinite()``,
+``isinf()``, ``isnan()``, ``round()``.
+Patch by Victor Stinner.
@@ -58,7 +58,6 @@ WIN32 is still required for the locale module.
 
 #include <io.h>
 
-#define HAVE_HYPOT
 #define HAVE_STRFTIME
 #define DONT_HAVE_SIG_ALARM
 #define DONT_HAVE_SIG_PAUSE
@@ -348,14 +347,6 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
 
 /* Fairly standard from here! */
 
-/* Define to 1 if you have the `copysign' function. */
-#define HAVE_COPYSIGN 1
-
-/* Define to 1 if you have the `round' function. */
-#if _MSC_VER >= 1800
-#  define HAVE_ROUND 1
-#endif
-
 /* Define if on AIX 3.
    System headers sometimes define this.
    We just want to avoid a redefinition error message.  */

diff --git a/Python/pymath.c b/Python/pymath.c
@@ -17,51 +17,3 @@ void _Py_set_387controlword(unsigned short cw) {
     __asm__ __volatile__ ("fldcw %0" : : "m" (cw));
 }
 #endif  // HAVE_GCC_ASM_FOR_X87
-
-
-#ifndef HAVE_HYPOT
-double hypot(double x, double y)
-{
-    double yx;
-
-    x = fabs(x);
-    y = fabs(y);
-    if (x < y) {
-        double temp = x;
-        x = y;
-        y = temp;
-    }
-    if (x == 0.)
-        return 0.;
-    else {
-        yx = y/x;
-        return x*sqrt(1.+yx*yx);
-    }
-}
-#endif /* HAVE_HYPOT */
-
-#ifndef HAVE_COPYSIGN
-double
-copysign(double x, double y)
-{
-    /* use atan2 to distinguish -0. from 0. */
-    if (y > 0. || (y == 0. && atan2(y, -1.) > 0.)) {
-        return fabs(x);
-    } else {
-        return -fabs(x);
-    }
-}
-#endif /* HAVE_COPYSIGN */
-
-#ifndef HAVE_ROUND
-double
-round(double x)
-{
-    double absx, y;
-    absx = fabs(x);
-    y = floor(absx);
-    if (absx - y >= 0.5)
-        y += 1.0;
-    return copysign(y, x);
-}
-#endif /* HAVE_ROUND */
@@ -15066,7 +15066,7 @@ fi
 LIBS_SAVE=$LIBS
 LIBS="$LIBS $LIBM"
 
-for ac_func in acosh asinh atanh copysign erf erfc expm1 finite gamma
+for ac_func in acosh asinh atanh erf erfc expm1 finite gamma
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
@@ -15078,7 +15078,7 @@ _ACEOF
 fi
 done
 
-for ac_func in hypot lgamma log1p log2 round tgamma
+for ac_func in lgamma log1p log2 tgamma
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

@@ -4675,8 +4675,8 @@ fi
 LIBS_SAVE=$LIBS
 LIBS="$LIBS $LIBM"
 
-AC_CHECK_FUNCS([acosh asinh atanh copysign erf erfc expm1 finite gamma])
-AC_CHECK_FUNCS([hypot lgamma log1p log2 round tgamma])
+AC_CHECK_FUNCS([acosh asinh atanh erf erfc expm1 finite gamma])
+AC_CHECK_FUNCS([lgamma log1p log2 tgamma])
 
 # For multiprocessing module, check that sem_open
 # actually works.  For FreeBSD versions <= 7.2,

diff --git a/pyconfig.h.in b/pyconfig.h.in
@@ -160,9 +160,6 @@
 /* Define to 1 if you have the <conio.h> header file. */
 #undef HAVE_CONIO_H
 
-/* Define to 1 if you have the `copysign' function. */
-#undef HAVE_COPYSIGN
-
 /* Define to 1 if you have the `copy_file_range' function. */
 #undef HAVE_COPY_FILE_RANGE
 
@@ -538,9 +535,6 @@
 /* Define this if you have le64toh() */
 #undef HAVE_HTOLE64
 
-/* Define to 1 if you have the `hypot' function. */
-#undef HAVE_HYPOT
-
 /* Define to 1 if you have the <ieeefp.h> header file. */
 #undef HAVE_IEEEFP_H
 
@@ -872,9 +866,6 @@
 /* Define if you have readline 4.0 */
 #undef HAVE_RL_RESIZE_TERMINAL
 
-/* Define to 1 if you have the `round' function. */
-#undef HAVE_ROUND
-
 /* Define to 1 if you have the `rtpSpawn' function. */
 #undef HAVE_RTPSPAWN