diff options
| author | Andy Wingo <wingo@pobox.com> | 2016-04-04 12:22:12 +0200 |
|---|---|---|
| committer | Andy Wingo <wingo@pobox.com> | 2016-04-04 16:30:57 +0200 |
| commit | 4bd903892535b1b1ddb7a7b09895e85e96736745 (patch) | |
| tree | 16469e292b1d6ed57b04a6f9d46688255ffdcf6a /libguile/poll.c | |
| parent | b77fb752dd7e14876741ecb6360ef0319eae18e0 (diff) | |
| download | guile-4bd903892535b1b1ddb7a7b09895e85e96736745.tar.gz | |
Fix POLLOUT assignment from port buffers
* libguile/poll.c (scm_primitive_poll): A buffered port's buffer marks
it as writable only when writing a byte would not block, which is the
case only if there is more than one byte free in the buffer; writing
the last byte would block.
Diffstat (limited to 'libguile/poll.c')
| -rw-r--r-- | libguile/poll.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/libguile/poll.c b/libguile/poll.c index 9ea846b6d..90a5c05e1 100644 --- a/libguile/poll.c +++ b/libguile/poll.c @@ -111,8 +111,10 @@ scm_primitive_poll (SCM pollfds, SCM nfds, SCM ports, SCM timeout) if (pt->read_pos < pt->read_end) /* Buffered input waiting to be read. */ revents |= POLLIN; - if (pt->write_pos < pt->write_end) - /* Buffered output possible. */ + if (SCM_OUTPUT_PORT_P (port) + && pt->write_end - pt->write_pos > 1) + /* Buffered output possible. The "> 1" is because + writing the last byte would flush the port. */ revents |= POLLOUT; } } @@ -147,8 +149,10 @@ scm_primitive_poll (SCM pollfds, SCM nfds, SCM ports, SCM timeout) if (pt->read_pos < pt->read_end) /* Buffered input waiting to be read. */ revents |= POLLIN; - if (SCM_OUTPUT_PORT_P (port) && pt->write_pos < pt->write_end) - /* Buffered output possible. */ + if (SCM_OUTPUT_PORT_P (port) + && pt->write_end - pt->write_pos > 1) + /* Buffered output possible. The "> 1" is because + writing the last byte would flush the port. */ revents |= POLLOUT; } } |