When opening the write end of a fifo that doesn't have a reader
already, the old implementation could allow writing bytes that are
discarded. This new implementation uses a blocking `open` in a
`pthread`, and that way the write routines know whether the stream is
ready for writing or not.
The difference is visible in the Racket API in a two places:
`subprocess` needs to wait until a fifo writer is connected before
attempting to dup the corresponding file descriotor, and more
generally a use of `unsafe-port->file-descriptor` needs to wait. The
former blocking operation is now build into `subprocess` (and
documented), but the burden is place on callers of
`unsafe-port->file-descriptor` to wait is necessary.
The new `port-waiting-peer?` predicate exposes the waiting state,
while `sync` is sufficient to wait for a peer.
Closes#2784
On platforms other than Windows and MacOS, locale encoding (inclduing
path <-> string conversion) opened a converter for each separate
operation. That can be slow on some OSes, so cache converters used for
locale conversions.
Relevant to #2781
Allowing #f as an allocator avoids problems composing `allocator` with
foreign-function lookup where failure is anticipated and implemented
as #f. For example, `g_settings_new` in the "gui-lib" package's
"mred/private/wx/gtk/gsettings.rkt" can be #f if the libgio libray is
too old, in which case there won't be an attempt to use
`g_settings_new`.
In some cases, (vector x 2 3 3 3) was pretty-printed as "(vector x 2 3)" when
print-vector-length was enabled.
Also print "(fxvector)" instead of "(fxvector )".
There may be still a string in the result-channel, because it is possible that the main thread exits before the result-thread calls `(channel-get result-channel)' and display its result.
This repair affects DrRacket and xrepl after `enter` so that a
`require` in the context of a module namespace is resolved relative to
the module's path (as it did in the old expander, before v7.0).
Closesracket/drracket#276
Fix the default argument in `syntax/template`, where cons-proc-stx should be a
syntax object reflecting a procedure, not a procedure itself.
Fix test case for `syntax/template`, where restore-stx should be a syntax object
reflecting the restore procedure, not the proceure itself.
Closes#2745
For now, the operation is implemented on mutable tables in Chez
using a combination of hashtable-contains? and hashtable-cell.
A more efficient version will require modifying Chez.
Compute the list (at compile time), instead of using a literal copy of
the output at one point.
Also, adjust the documentation to explain extra guarantees provided by
`make-known-char-range-list`.
Closes#2757
