Hi,
I've been successfully developing using APR-1.2.7 on Unix for the last
few months, and now I'm testing on Win/XP.
I'm launching processes like this:
apr_procattr_create (&attr, _pool);
// create pipes to read stdout and stderr
apr_procattr_io_set(attr, APR_NO_PIPE, APR_CHILD_BLOCK,
APR_CHILD_BLOCK);
apr_proc_t proc;
stat = apr_proc_create(&proc, argv[0], argv, envv, attr, _pool);
and then reading their output in a non-blocking loop in another thread
like this:
for (;;) {
apr_size_t nbytes = sizeof(buf);
stat = apr_file_read(_proc.out, buf, &nbytes);
if ((stat != APR_SUCCESS) || (nbytes == 0)) break;
_out.append(buf, nbytes);
}
}
This all works fine on Unix, but on Windows, the read blocks, even
although I call apr_procattr_io_set() to set the parent end of the pipes
to non-blocking.
The reason for this appears to be a problem in
apr_create_nt_pipe(file_io/win32/pipe.c), which initialises the
apr_file_t.timeout fields to -1 (blocking), and does not reset them to 0
(zero-timeout) if a non-blocking mode has been requested:
Setting these timeouts to zero in my application code, solves the
problem, although to do this I had to hack into the opaque
apr_procattr_t structure:
struct apr_procattr_hack {
apr_pool_t *pool;
apr_file_t *parent_in;
apr_file_t *child_in;
apr_file_t *parent_out;
apr_file_t *child_out;
apr_file_t *parent_err;
apr_file_t *child_err;
};
// add after apr_procattr_io_set() in first code snippet above
apr_file_pipe_timeout_set(((apr_procattr_hack*)attr)->parent_out, 0);
apr_file_pipe_timeout_set(((apr_procattr_hack*)attr)->parent_err, 0);
Can you confirm that this is a problem, or am I doing something wrong?
If it is a problem, should I log it as a bug?
Thanks,
Derek
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