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Problem with threaded program
- From: David Relson <relson at osagesoftware dot com>
- To: gdb at sources dot redhat dot com
- Date: Sun, 02 Dec 2001 11:44:19 -0500
- Subject: Problem with threaded program
Greetings,
The problem below was originally reported to the Linux Kernel Mailing
List. It looks to me to be a gdb problem.
I used a freshly compiled and installed copy of gdb-5.1 (configured as
"i686-pc-linux-gnu") for this test on a Pentium III 500mhz running the
2.4.16 kernel. The same problem happens with gdb-5.0. gdb-4.18 appears to
work fine.
Here's the test program, test.c:
#include <stdlib.h>
int main() {
char *t="1.0";
double d=0;
d=strtod(t,(char **)NULL);
printf( "%f\n", d );
return 0;
}
Build using "gcc -g -lpthread test.c"; run using "gdb a.out".
If you step through the program one line at a time and display variable d
after each assignment, the strtod() call seems to return
"nan(0x8000000000000)", which is also shown by print().
If you restart the program with a breakpoint at printf(), let it run, and
display d at the breakpoint, the value shown is "1.000000" which is correct.
Is this a defect in gdb, or is my analysis wrong?
David
P.S.
--------------------------------------------------------
David Relson Osage Software Systems, Inc.
relson@osagesoftware.com Ann Arbor, MI 48103
www.osagesoftware.com tel: 734.821.8800