Daniel Diaz-3 wrote:
A first remark without looking at details...
The gprolog version you downloaded is a native Windows app. It does
not know nothing about cygwin.
In particular bash or /bin cannot be resolved.
You can try passing 'c:/cygwin/bin/echo abc' to see if it is better.
For instance try:
exec('dir', I,O,E,P), repeat, get_char(O,T), write(T), T =
end_of_file, !, wait(P,S).
What do you obtain ?
Interesting, I get this:
$ gprolog
GNU Prolog 1.4.0
By Daniel Diaz
Copyright (C) 1999-2011 Daniel Diaz
| ?- exec('dir', I,O,E,P), repeat, get_char(O,T), write(T), T =
end_of_file, !, wait(P,S).
Volume in drive C is OS
Volume Serial Number is F44F-E564
Directory of C:\marku\starlog\trunk
12/12/2011 12:31 PM<DIR> .
12/12/2011 12:31 PM<DIR> ..
13/12/2011 02:13 PM<DIR> .svn
12/12/2011 12:30 PM<DIR> art
12/12/2011 12:31 PM<DIR> cuda
12/12/2011 12:31 PM<DIR> doc
...
0 File(s) 0 bytes
31 Dir(s) 314,787,344,384 bytes free
end_of_file
uncaught exception: error(system_error('No child processes'),wait/2)
| ?-
which shows that the exec is working, but the wait is not (perhaps the child
process is not being kept around as a zombie until the wait?)
or
exec('c:/cygwin/bin/echo abc', I,O,E,P), repeat, get_char(O,T),
write(T), T = end_of_file, !, wait(P,S).
What do you obtain ?
Same result.
I did this twice - the first time with a non-existent executable and the
second time with the correct path to cygwin echo.
$ gprolog
GNU Prolog 1.4.0
By Daniel Diaz
Copyright (C) 1999-2011 Daniel Diaz
| ?- exec('c:/cygwin/bin/echo abc', I,O,E,P), repeat, get_char(O,T),
write(T), T = end_of_file, !, wait(P,S).
end_of_file
uncaught exception: error(system_error('No child processes'),wait/2)
| ?- exec('c:/Apps/cygwin/bin/echo abc', I,O,E,P), repeat, get_char(O,T),
write(T), T = end_of_file, !, wait(P,S).
abc
end_of_file
uncaught exception: error(system_error('No child processes'),wait/2)
| ?-
If you want a pure cygwin app you should download a source .tar.gz
package and build it under cygwin.
Yes, I've tried that. It builds and installs successfully, but I get the
same problem with wait/2:
address@hidden /cygdrive/c/Apps/gprolog-1.4.0/src
$ which gprolog
/usr/local/bin/gprolog
$ gprolog
GNU Prolog 1.4.0
By Daniel Diaz
Copyright (C) 1999-2011 Daniel Diaz
| ?- exec('dir', I,O,E,P), repeat, get_char(O,T), write(T), T =
end_of_file, !, wait(P,S).
Volume in drive C is OS
Volume Serial Number is F44F-E564
Directory of C:\Apps\gprolog-1.4.0\src
14/12/2011 06:01 AM<DIR> .
14/12/2011 06:01 AM<DIR> ..
17/12/2008 02:36 AM 4,131 .indent.pro
18/06/1999 05:53 PM 7,832 AUTOCONF-INFO
14/12/2011 06:00 AM<DIR> BipsFD
14/12/2011 05:59 AM<DIR> BipsPl
...
22 File(s) 414,279 bytes
16 Dir(s) 314,768,809,984 bytes free
end_of_file
uncaught exception: error(system_error('No child processes'),wait/2)
| ?-
Does the gprolog 1.4.0 wait/2 call work on your Windows machine?
Ordinary C programs that use exec and wait seem to work fine,
for example the fork-03.c program here:
http://www.csl.mtu.edu/cs4411/www/NOTES/process/fork/wait.html seems to
produce the expected output.
Thanks
Mark