diff options
Diffstat (limited to 'lib/Support/raw_ostream.cpp')
| -rw-r--r-- | lib/Support/raw_ostream.cpp | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp index 14c6a10229..11cf0ec427 100644 --- a/lib/Support/raw_ostream.cpp +++ b/lib/Support/raw_ostream.cpp @@ -434,10 +434,13 @@ void raw_fd_ostream::write_impl(const char *Ptr, size_t Size) { if (ret < 0) { // If it's a recoverable error, swallow it and retry the write. - // EAGAIN and EWOULDBLOCK are not unambiguously recoverable, but - // some programs, such as bjam, assume that their child processes - // will treat them as if they are. If you don't want this code to - // spin, don't use O_NONBLOCK file descriptors with raw_ostream. + // + // Ideally we wouldn't ever see EAGAIN or EWOULDBLOCK here, since + // raw_ostream isn't designed to do non-blocking I/O. However, some + // programs, such as old versions of bjam, have mistakenly used + // O_NONBLOCK. For compatibility, emulate blocking semantics by + // spinning until the write succeeds. If you don't want spinning, + // don't use O_NONBLOCK file descriptors with raw_ostream. if (errno == EINTR || errno == EAGAIN #ifdef EWOULDBLOCK || errno == EWOULDBLOCK |