For certain APIs, the return value of the function does not distinguish
between failure (which populates errno) and other non-error conditions
(which do not set errno).
For example, `fgets` returns `NULL` both when an error has occurred, or
upon EOF. If `errno` is already `EINTR` for whatever reason, then
```
RetryAfterSignal(nullptr, fgets, ...);
```
on a stream that has reached EOF would infinite loop.
Fix this by setting `errno` to `0` before each attempt in
`RetryAfterSignal`.
Patch by Ricky Zhou!
Differential Revision: https://reviews.llvm.org/D48755
llvm-svn: 336479
inline auto RetryAfterSignal(const FailT &Fail, const Fun &F,
const Args &... As) -> decltype(F(As...)) {
decltype(F(As...)) Res;
- do
+ do {
+ errno = 0;
Res = F(As...);
- while (Res == Fail && errno == EINTR);
+ } while (Res == Fail && errno == EINTR);
return Res;
}
std::unique_ptr<int> P(RetryAfterSignal(nullptr, [] { return new int(47); }));
EXPECT_EQ(47, *P);
+
+ errno = EINTR;
+ EXPECT_EQ(-1, RetryAfterSignal(-1, [] { return -1; }));
}