[libc-commits] [libc] [libc][POSIX][poll.h] implement poll (PR #125118)

[Nick Desaulniers via libc-commits]

================
@@ -0,0 +1,49 @@
+//===-- Implementation of poll --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/poll/poll.h"
+
+#include "hdr/types/nfds_t.h"
+#include "hdr/types/struct_pollfd.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/OSUtil/syscall.h" // syscall_impl
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/errno/libc_errno.h"
+
+#include <sys/syscall.h> // SYS_poll, SYS_ppoll
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, poll, (pollfd * fds, nfds_t nfds, int timeout)) {
+
+#ifdef SYS_poll
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_poll, fds, nfds, timeout);
+#elif defined(SYS_ppoll)
+  timespec ts, *tsp;
+  if (timeout >= 0) {
+    ts.tv_sec = timeout / 1000;
+    ts.tv_nsec = (timeout % 1000) * 1000000;
+    tsp = &ts;
+  } else {
+    tsp = nullptr;
+  }
+  int ret =
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_ppoll, fds, nfds, tsp, nullptr, 0);
+#else
+#error "SYS_ppoll_time64?"
----------------
nickdesaulniers wrote:

of course, 32b riscv doesn't have `poll` or `ppoll`.
https://lab.llvm.org/buildbot/#/builders/196/builds/4601/steps/4/logs/stdio
Just going to file a TODO and remove the entrypoint from riscv for now.

https://github.com/llvm/llvm-project/pull/125118