Re: [Valgrind-users] valgind with LD_PRELOAD

[John R. <jr...@bi...>]

> LD_PRELOAD=./libfake.so ./my_process --> runs fine and prints memory stats
> 
> But,
> 
> LD_PRELOAD=./libfake.so valgrind ./my_process --> doesnt print the memory stats
> 
>  From few online blogs, i understand that valgrind does forward any signals to the child process that it is running on but it doesnt seem to work here.

There is no parent-child relationship between valgrind and ./my_process.
Both valgrind and ./my_process run in the same address space as just one process.
The inter-process communication would be extremely expensive if valgrind
and ./my_process did not share the same address space, and memcheck tracking
of each memory access would be difficult if there were 2 threads of control.

The command-line parameter "--trace-signals=yes" causes valgrind to report on signals.
The Linux utility /usr/bin/strace also reports on signals.  (Probably use
something like "strace -e trace=file" to reduce the syscalls that strace reports;
in particular 'read' and 'write' are usually heavily used and ignorable.)