Why do I get different behavior when I compile and run hello.cpp (see below)
two different
ways:
g++f4 -c -fmudflap -o hello.o hello.cpp ; g++f4 -o hello hello.o -lmudflap
g++f4 -fmudflap -o hello hello.cpp -lmudflap
When I compile the first way, I get mudflap warnings when I access argv[0]
and errno; when I compile the second way, mudflap is silent. Should I
expect to see mudflap warnings with errno accesses? I have an application
that accesses it frequently so I get a huge number of warnings.
Thanks...
David
PS - I was using gcc from svn from 2006-02-03.
#include <stdio.h>
#include <errno.h>
int main(int argc, char *argv[])
{
errno = 1;
printf("%d %s\n", errno, argv[0]);
printf("Hello, world!\n");
return 0;
}
{65} g++f4 -c -fmudflap -o hello.o hello.cpp ; g++f4 -o hello hello.o
-lmudflap
{66} ./hello
*******
mudflap violation 1 (check/write): time=1139021256.756465 ptr=0xb7e926a0
size=4
pc=0xb7ebc322 location=`hello.cpp:6 (main)'
/usr/lib/libmudflap.so.0(__mf_check+0x44) [0xb7ebc322]
./hello(main+0x92) [0x8048776]
/lib/tls/libc.so.6(__libc_start_main+0xd3) [0xbdae23]
number of nearby objects: 0
*******
mudflap violation 2 (check/read): time=1139021256.757309 ptr=0xbf898d64
size=4
pc=0xb7ebc322 location=`hello.cpp:7 (main)'
/usr/lib/libmudflap.so.0(__mf_check+0x44) [0xb7ebc322]
./hello(main+0x117) [0x80487fb]
/lib/tls/libc.so.6(__libc_start_main+0xd3) [0xbdae23]
number of nearby objects: 0
*******
mudflap violation 3 (check/read): time=1139021256.757390 ptr=0xb7e926a0
size=4
pc=0xb7ebc322 location=`hello.cpp:7 (main)'
/usr/lib/libmudflap.so.0(__mf_check+0x44) [0xb7ebc322]
./hello(main+0x1a0) [0x8048884]
/lib/tls/libc.so.6(__libc_start_main+0xd3) [0xbdae23]
number of nearby objects: 0
1 ./hello
Hello, world!
{67} g++f4 -fmudflap -o hello hello.cpp -lmudflap
{68} ./hello
1 ./hello
Hello, world!
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