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).
(cherry picked from commit f57cd8288dbe6aba99c057f37ad6d58f8db75350)
Co-authored-by: Dima Pasechnik <dimpase@gmail.com>
diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 5d9fe5a..9eaeff1 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -77,7 +77,7 @@
#endif /* !defined(HAVE_ERF) || !defined(HAVE_ERFC) */
static double
-sinpi(double x)
+m_sinpi(double x)
{
double y, r;
int n;
@@ -305,7 +305,7 @@
integer. */
if (absx > 200.0) {
if (x < 0.0) {
- return 0.0/sinpi(x);
+ return 0.0/m_sinpi(x);
}
else {
errno = ERANGE;
@@ -329,7 +329,7 @@
}
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);
@@ -400,7 +400,7 @@
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;