I have two questions. First, I am trying to create and map some files
under program
control using the jmf utilities. Sometimes when I create a jmf file and
then try to
map it to a variable name I get a "bad jmf header" error message. When I
try the
map_jmf_ operation manually rather than in the program, but using the jmf
file
created by the program, it also gives the "bad jmf header" message. But
if I create
the jmf file manually and then map it manually, it works. So the problem
seems to
have something to do with the create_jmf_ step's working differently
within a program
than without.
My second question involves using 7!:5 to estimate the file size necessary
for the
mapped file to hold a particular boxed array. (There is no problem with
numeric or
character arrays as I can just multiply their number of elements by JINT,
JFL, JCHAR,
etc.). I hope the figures given by 7!:5 will be sufficient to avoid
allocation
errors, but I am puzzled by behavior like the following:
(1200$<a.)-:1200$<256{.a.
1
(1200$<' ')-:1200$<32{a.
1
(1200$<' ')-:1200$<32{a.
1
x=.1200$<256{.a.
7!:5 <'x'
8192
x=.1200$<256{.a.
7!:5 <'x'
622592
x=.1200$<256$a.
7!:5 <'x'
622592
x=.1200$<128$a.
7!:5 <'x'
315392
x=.1200$<' '
7!:5 <'x'
8192
x=.1200$<32{a.
7!:5 <'x'
84992
etc.
Granted that boxed arrays can sometimes require much more space than
unboxed arrays, it does seem strange that
the size required should depend on how the arrays were originally
constructed, before being assigned to a noun.
Dick Vaughan
This message is intended only for the addressee and may contain information
that is confidential or privileged. Unauthorized use is strictly prohibited and
may be unlawful. If you are not the intended recipient, or the person
responsible for delivering to the intended recipient, you should not read,
copy, disclose or otherwise use this message, except for the purpose of
delivery to the addressee. If you have received this email in error, please
delete and advise the IT Security department at [EMAIL PROTECTED] immediately.
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
