diff options
| author | simonmar <unknown> | 2000-05-11 13:15:38 +0000 |
|---|---|---|
| committer | simonmar <unknown> | 2000-05-11 13:15:38 +0000 |
| commit | 0eb4bba10f3d6c9143d73fb8cadb11eba1a5dbd9 (patch) | |
| tree | 7ac7aa7d4282ac02f7936430ad8a781fccc6e8fc /ghc/lib/std/cbits/openFile.c | |
| parent | 3baf75550726b484e03e69d9378384d8b45f8052 (diff) | |
| download | haskell-0eb4bba10f3d6c9143d73fb8cadb11eba1a5dbd9.tar.gz | |
[project @ 2000-05-11 13:15:38 by simonmar]
Don't open with O_NONBLOCK, instead open in blocking mode and set
O_NONBLOCK subsequently with fcntl(). This appears to fix the
problems with FIFOs.
Pick one of the following:
- the semantics as implemented by Linux & Solaris is broken
- the POSIX semantics is broken
- our expectation that things should behave sensibly is unreasonable
Diffstat (limited to 'ghc/lib/std/cbits/openFile.c')
| -rw-r--r-- | ghc/lib/std/cbits/openFile.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/ghc/lib/std/cbits/openFile.c b/ghc/lib/std/cbits/openFile.c index 8930fe568d..57b0c2ff84 100644 --- a/ghc/lib/std/cbits/openFile.c +++ b/ghc/lib/std/cbits/openFile.c @@ -1,7 +1,7 @@ /* * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998 * - * $Id: openFile.c,v 1.16 2000/04/12 17:33:16 simonmar Exp $ + * $Id: openFile.c,v 1.17 2000/05/11 13:15:38 simonmar Exp $ * * openFile Runtime Support */ @@ -94,22 +94,22 @@ openFile(StgByteArray file, StgInt how, StgInt binary) switch (how) { case OPENFILE_APPEND: - oflags = O_NONBLOCK | O_WRONLY | O_NOCTTY | O_APPEND; + oflags = O_WRONLY | O_NOCTTY | O_APPEND; for_writing = 1; flags |= FILEOBJ_WRITE; break; case OPENFILE_WRITE: - oflags = O_NONBLOCK | O_WRONLY | O_NOCTTY; + oflags = O_WRONLY | O_NOCTTY; flags |= FILEOBJ_WRITE; for_writing = 1; break; case OPENFILE_READ_ONLY: - oflags = O_NONBLOCK | O_RDONLY | O_NOCTTY; + oflags = O_RDONLY | O_NOCTTY; flags |= FILEOBJ_READ; for_writing = 0; break; case OPENFILE_READ_WRITE: - oflags = O_NONBLOCK | O_RDWR | O_NOCTTY; + oflags = O_RDWR | O_NOCTTY; flags |= FILEOBJ_READ | FILEOBJ_WRITE; for_writing = 1; break; @@ -191,8 +191,17 @@ openFile(StgByteArray file, StgInt how, StgInt binary) } } - /* Make sure that we aren't looking at a directory */ + /* Set non-blocking mode *after* the open. The reason is that + * when reading from a FIFO, if we open in non-blocking mode + * then any reads from the FIFO will return EOF straight away + * without waiting for a writing process. If we set O_NONBLOCK + * after doing the open, then we apparently get to wait for a + * writer. This broken behaviour has been observed on both Linux + * & Solaris. --SDM + */ + fcntl(fd, F_SETFL, oflags | O_NONBLOCK); + /* Make sure that we aren't looking at a directory */ while (fstat(fd, &sb) < 0) { /* highly unlikely */ if (errno != EINTR) { |