Gprolog 1.4 exec/5 does not work under cygwin

[Mark Utting]

I'm trying to upgrade to Gprolog 1.4, but my exec calls to a theorem prover have stopped working.

In fact, every exec/5 call seems not to work, and causes wait/2 to throw an error as the following 2 examples show:

===================================================
$ gprolog
GNU Prolog 1.4.0
By Daniel Diaz
Copyright (C) 1999-2011 Daniel Diaz
| ?- exec('bash query_Simplify.sh simplifyFile.smp', A, B, C, PID).

A = '$stream'(3)
B = '$stream'(4)
C = '$stream'(5)
PID = 5972

yes
| ?- wait(5972, Status).
uncaught exception: error(system_error('No child processes'),wait/2)


# even /bin/echo gives the same error

| ?- exec('/bin/echo abc', A,B,C,D).

A = '$stream'(9)
B = '$stream'(10)
C = '$stream'(11)
D = 7564

yes
| ?- wait(7564).
uncaught exception: error(existence_error(procedure,wait/1),top_level/0)
| ?- wait(7564, Status).
uncaught exception: error(system_error('No child processes'),wait/2)
| ?- exec('/bin/echo', A,B,C,D).

A = '$stream'(12)
B = '$stream'(13)
C = '$stream'(14)
D = 4900

yes
| ?- wait(4900, Status).
uncaught exception: error(system_error('No child processes'),wait/2)
| ?-
=======================================================

The above exec of 'bash query_Simplify.sh simplifyFile.smp' worked fine with Gprolog 1.3.
(and that command works from the command line).

Any suggestions how I can work around this problem?


I'm using the binary 64-bit Windows version of GProlog 1.4.0:
Windows intel 64 bits auto-install setup (compiled under x86_64 / Windows 7 with MinGW64 gcc under Cygwin).

This is under Windows 7 64-bit with an up-to-date Cygwin, and Mingw 64-bit gcc installed (the gprolog and gplc commands work fine).

$ uname -a
CYGWIN_NT-6.1-WOW64 RWS034 1.7.9(0.237/5/3) 2011-03-29 10:10 i686 Cygwin

Thanks!
Mark