Lisp IO problem - lisp

Question

I am a lisp noob trying to learn lisp using sbcl v1.0.50.
I am writing a simple logger and running into a memory fault which
I do not understand, but which seems to be related to how I compile my
script. I have boiled it down to the following:
===logger.lisp===
(defparameter *log-stream* (open "/tmp/global-log"
:direction :output
:if-does-not-exist :create
:if-exists :append))
===main.lisp===
(load "logger.lisp")
(defun main ()
(format *log-stream* "Hello world~%"))
==compile.lisp==
#! /usr/bin/sbcl --script
(load "main.lisp")
(save-lisp-and-die "program" :toplevel #'main :executable t)
When I compile and run the program it crashes:
> ./compile.lisp
[undoing binding stack and other enclosing state... done]
[saving current Lisp image into foo:
writing 6352 bytes from the read-only space at 0x20000000
writing 4064 bytes from the static space at 0x20100000
writing 43057152 bytes from the dynamic space at 0x1000000000
> ./program
CORRUPTION WARNING in SBCL pid 21860(tid 140737353914112):
Memory fault at f6977000 (pc=0x1000036365, sp=0x7ffff6b7f8d0)
The integrity of this image is possibly compromised.
Continuing with fingers crossed.
unhandled SB-SYS:MEMORY-FAULT-ERROR in thread #<SB-THREAD:THREAD
"initial thread" RUNNING
{10029118D1}>:
Unhandled memory fault at #x7FFFF6977000.
0: (SB-DEBUG::MAP-BACKTRACE
#<CLOSURE (LAMBDA #) {100291A3C9}>
:START
0
:COUNT
128)
1: (BACKTRACE 128 #<SYNONYM-STREAM :SYMBOL SB-SYS:*STDERR* {100001CEB1}>)
2: (SB-DEBUG::DEBUGGER-DISABLED-HOOK
#<SB-SYS:MEMORY-FAULT-ERROR {10029180E1}>
#<unavailable argument>)
3: (SB-DEBUG::RUN-HOOK
*INVOKE-DEBUGGER-HOOK*
#<SB-SYS:MEMORY-FAULT-ERROR {10029180E1}>)
4: (INVOKE-DEBUGGER #<SB-SYS:MEMORY-FAULT-ERROR {10029180E1}>)
5: (ERROR SB-SYS:MEMORY-FAULT-ERROR :ADDRESS 140737330507776)
6: (SB-SYS:MEMORY-FAULT-ERROR)
7: ("foreign function: #x4174A0")
8: ("foreign function: #x417580")
9: (SB-IMPL::OUTPUT-BYTES/UTF-8
#<SB-SYS:FD-STREAM for "file /tmp/global-log" {10001B8A81}>
"AAAA"
NIL
0
4)
10: (SB-IMPL::FD-SOUT
#<SB-SYS:FD-STREAM for "file /tmp/global-log" {10001B8A81}>
"AAAA"
0
4)
11: (SB-IMPL::%WRITE-STRING
"AAAA"
#<SB-SYS:FD-STREAM for "file /tmp/global-log" {10001B8A81}>
0
NIL)
12: ((LAMBDA (STREAM &OPTIONAL &REST SB-FORMAT::ARGS))
#<SB-SYS:FD-STREAM for "file /tmp/global-log" {10001B8A81}>)
13: (FORMAT
#<SB-SYS:FD-STREAM for "file /tmp/global-log" {10001B8A81}>
#<FUNCTION (LAMBDA #) {100002F6C9}>)
14: ((FLET #:WITHOUT-INTERRUPTS-BODY-[RESTART-LISP]30))
15: ((LABELS SB-IMPL::RESTART-LISP))
unhandled condition in --disable-debugger mode, quitting
I have tried for a while to understand what is going on, but hmm. Help
would be appreciated!
Anders

Answer 1

You open a stream and then you dump an image.
Then you start the dumped image and try to write to the stream.
You can't expect that the stream stays open between program runs or gets automatically opened somehow when you start an image.
If you start the image, open the stream and then write to it.
See also the macro WITH-OPEN-FILE.
You may also want to discuss this on the SBCL mailing list. SBCL should give a better error report.
Generally you need to understand how dumping an image works and what the restrictions are. Typically one can't:
dump the state of open streams
keep network connections open
keep windows open
and more...