Home »
Public Forums »
archive »
Strange bug in IDL or AIX
| Strange bug in IDL or AIX [message #231] |
Mon, 03 February 1992 02:10 |
dov
Messages: 4
Registered: February 1992
|
Junior Member |
|
|
I have encountered a very strange bug. I don't know if it belongs
to IDL or AIX. It occurs when I use call_external from IDL.
Here is my idl program bug.pro:
--
1: a=call_external('./bug', ' ')
2:
3: end
--
And here is my external routine bug.c:
--
1: #include <math.h>
2:
3: bugsub(double *r)
4: {
5: *r= sqrt(5.0);
6: }
7:
8: bug(int argc, void *argv[])
9: {
10: }
--
I compile and link the c program with the sequence of commands
cc -O -c bug.c
ld -e bug -o bug bug.o -lm -lc
and then I try to run the program from idl. Here a copy of
idl's output:
IDL> .run bug
% Compiled module: $MAIN$.
% CALL_EXTERNAL: Error loading sharable executable.
Symbol: <not relevant>, File = ./bug
Exec format error
% Execution halted at $MAIN$ <bug2.pro( 1)> (CALL_EXTERNAL).
IDL>
But here comes the strange part. There are several ways this bug can
dissappear. If I change line 5 of bug.c to read:
5: *r=sin(5.0);
the bug dissappears!
The output from idl follows:
IDL> .run bug
% Compiled module: $MAIN$.
IDL>
Or if line 3 and 5 are changed to
3: bugsub(double r)
5: r=sqrt(5.0)
the bug also doesn't appear.
Neither does it appear if line 3 and 4 are changed to (the only
workaround of the bug that I have found...)
3: bugsub(double *rr)
4: { double *r; r=rr;
Does anybody have any idea what is going on here? Where is the bug?
Why is there a difference between sqrt() and sin()?
--
___ ___
/ o \ o \
Dov Grobgeld ( o o ) o |
The Weizmann Institute of Science, Israel \ o /o o /
"Where the tree of wisdom carries oranges" | | | |
_| |_ _| |_
|
|
|
|
Current Time: Wed Oct 08 15:31:39 PDT 2025
Total time taken to generate the page: 0.00609 seconds
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
