[Python-checkins] bpo-36106: Resolve sinpi name clash with libm (IEEE-754 violation). (GH-12027)
Serhiy Storchaka
webhook-mailer at python.org
Tue Feb 26 01:36:18 EST 2019
https://github.com/python/cpython/commit/f57cd8288dbe6aba99c057f37ad6d58f8db75350
commit: f57cd8288dbe6aba99c057f37ad6d58f8db75350
branch: master
author: Dima Pasechnik <dimpase at gmail.com>
committer: Serhiy Storchaka <storchaka at gmail.com>
date: 2019-02-26T08:36:11+02:00
summary:
bpo-36106: Resolve sinpi name clash with libm (IEEE-754 violation). (GH-12027)
The standard math library (libm) may follow IEEE-754 recommendation to
include an implementation of sinPi(), i.e. sinPi(x):=sin(pi*x).
And this triggers a name clash, found by FreeBSD developer
Steve Kargl, who worken on putting sinpi into libm used on FreeBSD
(it has to be named "sinpi", not "sinPi", cf. e.g.
https://en.cppreference.com/w/c/experimental/fpext4).
files:
A Misc/NEWS.d/next/Library/2019-02-25-13-21-43.bpo-36106.VuhEiQ.rst
M Modules/mathmodule.c
diff --git a/Misc/NEWS.d/next/Library/2019-02-25-13-21-43.bpo-36106.VuhEiQ.rst b/Misc/NEWS.d/next/Library/2019-02-25-13-21-43.bpo-36106.VuhEiQ.rst
new file mode 100644
index 000000000000..36e17508cd4a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-02-25-13-21-43.bpo-36106.VuhEiQ.rst
@@ -0,0 +1 @@
+Resolve potential name clash with libm's sinpi(). Patch by Dmitrii Pasechnik.
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 2272f622f0b9..fd0eb327c743 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -100,7 +100,7 @@ static const double sqrtpi = 1.772453850905516027298167483341145182798;
}
static double
-sinpi(double x)
+m_sinpi(double x)
{
double y, r;
int n;
@@ -328,7 +328,7 @@ m_tgamma(double x)
integer. */
if (absx > 200.0) {
if (x < 0.0) {
- return 0.0/sinpi(x);
+ return 0.0/m_sinpi(x);
}
else {
errno = ERANGE;
@@ -352,7 +352,7 @@ m_tgamma(double x)
}
z = z * lanczos_g / y;
if (x < 0.0) {
- r = -pi / sinpi(absx) / absx * exp(y) / lanczos_sum(absx);
+ r = -pi / m_sinpi(absx) / absx * exp(y) / lanczos_sum(absx);
r -= z * r;
if (absx < 140.0) {
r /= pow(y, absx - 0.5);
@@ -423,7 +423,7 @@ m_lgamma(double x)
r += (absx - 0.5) * (log(absx + lanczos_g - 0.5) - 1);
if (x < 0.0)
/* Use reflection formula to get value for negative x. */
- r = logpi - log(fabs(sinpi(absx))) - log(absx) - r;
+ r = logpi - log(fabs(m_sinpi(absx))) - log(absx) - r;
if (Py_IS_INFINITY(r))
errno = ERANGE;
return r;
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