Andrew Morrow: The attached patch is an attempt to implement
std::thread::hardware_concurrency for platforms that don't offer
sysctl, but do provide a POSIX sysconf and _SC_NPROCESSORS_ONLN.
llvm-svn: 161190
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: d3673eb4e1716bd727e4bae276bc2798afe3c7c0
diff --git a/src/thread.cpp b/src/thread.cpp
index ffcbe0a..4445b8d 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -12,9 +12,13 @@
#include "vector"
#include "future"
#include <sys/types.h>
-#if !_WIN32 && !__sun__
+#if !_WIN32
+#if !__sun__ && !__linux__
#include <sys/sysctl.h>
-#endif // _WIN32
+#else
+#include <unistd.h>
+#endif // !__sun__ && !__linux__
+#endif // !_WIN32
_LIBCPP_BEGIN_NAMESPACE_STD
@@ -60,6 +64,11 @@
std::size_t s = sizeof(n);
sysctl(mib, 2, &n, &s, 0, 0);
return n;
+#elif defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE >= 200112L) && defined(_SC_NPROCESSORS_ONLN)
+ long result = sysconf(_SC_NPROCESSORS_ONLN);
+ if (result < 0 || result > UINT_MAX)
+ result = 0;
+ return result;
#else // defined(CTL_HW) && defined(HW_NCPU)
// TODO: grovel through /proc or check cpuid on x86 and similar
// instructions on other architectures.