307 lines
11 KiB
Plaintext
307 lines
11 KiB
Plaintext
Scsh 0.6.2 Release notes -*- outline -*-
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We are pleased to release scsh version 0.6.2. This release
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incorporates many SRFIs into scsh. The enhanced module language of the
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recent Scheme 48 releases is now part of scsh. In addition most of the
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known bugs of the previous version have been fixed.
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The text below gives a general description of scsh, instructions for obtaining
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it, pointers to discussion forums, and a description of the new features in
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release 0.6.2. (Emacs should display this document is in outline mode. Say
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c-h m for instructions on how to move through it by sections (e.g., c-c c-n,
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c-c c-p).)
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* Contents
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==========
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What is scsh
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Scsh as a scripting language
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Scsh as a systems-programming language
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Scsh is a portable programming environment
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Obtaining and installing scsh
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Getting in touch
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The World-Wide What?
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New in this release
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SRFIs
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port->socket
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New forms in the module language
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API changes
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PDF version of the manual
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Bugfixes
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New in 0.6.1
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New in 0.6.0
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Thanks
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* What is scsh
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==============
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Scsh is a broad-spectrum systems-programming environment for Unix embedded
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in R5RS Scheme. It has an open-source copyright, and runs on most major
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Unix systems.
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** Scsh as a scripting language
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-------------------------------
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Scsh has a high-level process notation for doing shell-script like tasks:
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running programs, establishing pipelines and I/O redirection. For example, the
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shell pipeline
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gunzip < paper.tex.gz | detex | spell | lpr -Ppulp &
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would be written in scsh as
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(& (| (gunzip) (detex) (spell) (lpr -Ppulp)) ; Background a pipeline
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(< paper.tex.gz)) ; with this redirection
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Scsh embeds this process notation within a full Scheme implementation.
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The process notation is realized as a set of macro definitions, and is
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carefully designed to allow full integration with standard Scheme code.
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Scsh isn't Scheme-like; it is Scheme.
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At the scripting level, scsh also has an Awk design, also implemented
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as a macro that can be embedded inside general Scheme code.
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Scripts can be written as standalone Scheme source files, with a leading
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#!/usr/local/bin/scsh -s
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trigger line.
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** Scsh as a systems-programming language
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-----------------------------------------
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Scsh additionally provides the low-level access to the operating system
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normally associated with C. The current release provides full access to Posix,
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plus important non-Posix extensions, such as complete sockets support.
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"Complete Posix" means: fork, exec & wait, sockets, full read, write, open &
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close, seek & tell, complete file-system access, including stat,
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chmod/chgrp/chown, symlink, FIFO & directory access, tty & pty support, file
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locking, pipes, select, file-name pattern-matching, time & date, environment
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variables, signal handlers, and more.
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In brief, you can now write Unix systems programs in Scheme instead of C.
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For example, we have implemented an extensible HTTP server at MIT entirely
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in scsh.
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As important as full access to the OS is the manner in which it is provided.
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Scsh integrates the OS support into Scheme in a manner which respects the
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general structure of the language. The details of the design are discussed
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in a joint MIT Lab for Computer Science/University of Hong Kong technical
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report, "A Scheme Shell," also to appear in a revised format in the "Journal
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of Lisp and Symbolic Computation." This paper is also available by ftp:
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ftp://ftp.scsh.net/pub/scsh/papers/scsh-paper.ps
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** Scsh is a portable programming environment
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---------------------------------------------
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Scsh is designed for portability. It is implemented on top of Scheme 48,
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a byte-code-interpreter Scheme implementation. The Scheme 48 virtual machine
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can be compiled on any system with a C compiler; the rest of Scheme 48 is
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machine-independent across 32-bit processors. Scsh's OS interface is
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also quite portable, providing a consistent interface across different
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Unix platforms. We currently have scsh implementations for:
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AIX
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BSD/OS
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CXUX
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FreeBSD
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HP-UX
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IRIX
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Linux
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NetBSD
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Solaris
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SunOS
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Ultrix
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Win32
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Darwin/Mac OS X
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Scsh code should run without change across these systems.
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Porting to new platforms is usually not difficult.
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* Obtaining and installing scsh
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===============================
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You can get a copy of scsh via anonymous ftp, from
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ftp://ftp.scsh.net/pub/scsh/scsh.tar.gz
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The tar file includes a detailed manual and a paper describing
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the design of the system.
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For the lazily curious, we also have the manual separately available as
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ftp://ftp.scsh.net/pub/scsh/0.6/scsh-manual.ps
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Just click 'n view.
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You *should* be able to build scsh on the standard platforms with exactly five
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commands: gunzip, tar, cd, ./configure, and make. The configure script figures
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out the special flags and switches needed to make the build work (thanks to
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the GNU project for the autoconfig tool that makes this possible).
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After doing the make, you can start up a Scheme shell and try it out
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by saying
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./go
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See the manual for full details on the command-line switches.
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If it's harder than this, and your system is standard, we'd like to know
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about it.
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* Getting in touch
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==================
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There are two main ways to join in scsh-related discussion: the mailing-list
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scsh@zurich.ai.mit.edu
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and the netnews group
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comp.lang.scheme.scsh
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These two forums should be equivalent, being bi-directionally gatewayed
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at MIT, but due to technical problems it's better to read them both.
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Bugs can be reported to
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scsh-bugs@zurich.ai.mit.edu
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or via the Scsh project's bugs section on SourceForge:
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http://sourceforge.net/projects/scsh/
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If you do not netnews hierarchy, or wish to join the mailing
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list for other reasons, send mail to
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scsh-request@zurich.ai.mit.edu
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* The World-Wide What?
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======================
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We even have one of those dot-com cyberweb things:
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http://www.scsh.net
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We manage the project using SourceForge:
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http://sourceforge.net/projects/scsh/
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* New in this release
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=====================
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** SRFIs
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In addition to SRFI 1, 8, 13, 14 and 23 scsh now features SRFI 2,
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5, 6, 7, 9, 11, 16, 17 and 19. See http://srfi.schemers.org/ for a
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detailed description. The SRFIs are available in packages srfi-X
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where X is the number of the SRFI.
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** port->socket
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New procedure port->socket to turn a port into a socket object was
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added to the network code.
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** New forms in the module language
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The module language supports the new forms modify, subset and
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with-prefix from Scheme 48 version 0.57.
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** API changes
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Fork, fork/pipe, fork/pipe+ take an optional argument
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continue-threads? to determine whether all threads should continue
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to run in the child.
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** PDF version of the manual
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There is now a PDF version of the manual generated by pdflatex.
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** Bugfixes
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- Added default argument to tty-info as described in the manual
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- Conversion to s48_value in tty1.c
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- Fixed another hygiene problem in SRE
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- Plugged space leak in bind-listen-accept-loop
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- Aligned CWD and umask in various file operations
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- Better releasing of port locks
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- Corrected exception of time
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- Set-cloexec to #t for unrevealed ports.
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- Include scsh paper in the distribution.
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* New in 0.6.1
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==============
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** API changes
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For sre's, BOW, EOW, WORD, and WORD+ (which were already unsupported
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in 0.6.0 on most platforms) are gone for good.
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** Bugfixes
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Most of the known bugs of version 0.6.0 have been fixed, many thanks for
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the precise reports! See the project page on SourceForge for a list
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of the remaining known bugs. Here is a brief overview of the fixes:
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- GC_PROTECT'ed the necessary variables (specifically, where >1 arg to
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a function 'may GC') (Thanks to Steven Jenkins for dealing with this)
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- Fixed various race conditons in the signal handling and process reaping code
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- Fixed bug in set-process-group
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- If $HOME is unset, consult (user-info (user-uid)) for the value of
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home-directory
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- Fix external-call-from-callback problem leading to spurious
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gc-protection-mismatch exceptions.
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- Let s48-do-gc return 0 so the PreScheme compiler will emit the correct
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signature of the function.
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- scsh/linux/tty-consts.scm: num-ttychars seems to be 32 not 19.
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- scsh/top.scm: Return 0 exit status for -c and -e.
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- *.c: Replaced // comments.
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- scsh/syslog1.c: Remove LOG_LPR from list of syslog levels.
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- scsh/network1.c: Pass SYSCALL argument to ERRNO-ERROR.
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- scsh/syscalls1.c: Disable timer interrupts before execve
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- scsh/network.scm: Correct name extraction in bind-socket
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- Added export for with-error-output-port
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- Install HTML version of manual under $(libdir)
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- ./configure is more rebost wrt $(srcdir)
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- Fixed installation of the S48 manual
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- Replaced several /tmp by /var/tmp
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- Catch EISDIR in delete-filesys-object
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- flush-all-ports is now non-blocking
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* New in 0.6.0
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==============
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** Scsh is now based on Scheme 48 0.53
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With the move from Scheme 48 version 0.36 to version 0.53 in this
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release the underlying system received a massive update. The most
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significant changes include:
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User level threads
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Advanced garbage collector
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Improved foreign function interface to C
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The most significant change for Scsh users is the addition of a
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user-level thread system. Scsh provides various features to deal
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with this new power in a system programming environment: An event
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based interface to interrupts, thread local process state and
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thread-safe system calls.
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** A manual for Scheme 48 has been included
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Richard Kelsey, the author of Scheme 48, has graciously allowed us
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to retrofit the current Scheme 48 manual for inclusion in this scsh
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release.
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** Interfaces to dot-locking, crypt and syslog
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Scsh now provides advisory file locking via the dot-locking scheme
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and a direct binding to the crypt function. Furthermore we added
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a complete, system-independent and thread-safe interface to syslog.
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** API changes
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Some features of the previous releases are currently not
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supported as we did not have the time to implement them. Please tell
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us, if you can't get along without them. Here is a listing of these
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currently dereleased features:
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select
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select!
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ODBC support
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bufpol/line
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The following procedures received new names in this release:
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sleep (now process-sleep)
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sleep-until (now process-sleep-until)
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network-info, service-info and protocol-info now return #f on non-success.
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The default directory for creating temporary files has changed: It's
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now the value of $TMPDIR if set and /var/tmp otherwise.
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The nth procedure is still there but is now officially obsolete. It
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will go away in a future release.
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** HTML version of the manual
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There is now a HTML version of the scsh manual generated by tex2page
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* Thanks
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========
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We would like to thank the members of local-resistance cells for the
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Underground everywhere for bug reports, bug fixes, design review and comments
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that were incorporated into this release. We really appreciate their help,
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particularly in the task of porting scsh to new platforms.
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Brought to you by the Scheme Underground. Go forth and write elegant systems
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programs.
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-Olin Shivers, Brian Carlstrom, Martin Gasbichler & Mike Sperber
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