signal and STL constructors conflict causing deadlock

[Honigstein, Bat-sheva]

Hi!

        I'm trying to create a timer, using signal (SIGALARM). In that timer
a string is allocated. At the same time the main flow is also allocating
strings. (This, of course, is a small example of a much more complex issue).
When I compile my file with g++ sigmalloc.cpp -lpthread, I get a deadlock
caused by the fact that the main flow was interrupted by the signal while in
the string constructor.

        Some research has shown that I should use -D__USE_MALLOC in
compilation. This does, indeed, solve the deadlock. However, as I tried to
compile my code on RedHat 8 I received the following error: 
        "In file included from /usr/include/c++/3.2/iostream:44,
                 from /usr/include/c++/3.2/backward/iostream.h:32,
                 from sigmalloc.cpp:7:
/usr/include/c++/3.2/i386-redhat-linux/bits/c++config.h:74:2: #error
__USE_MALLOC should only be defined within
libstdc++-v3/include/bits/c++config before full recompilation of the
library."

        I would appreciate any advice!

        Thanks a lot!
----------------------------------------------------------------------------
--------------------------
My code:

#include <pthread.h>
#include <unistd.h>
#include <signal.h>
#include <iostream.h>
#include <string>

using namespace std;

void sig(int q)
{
    string s = "SIG!";
    cout << s << endl;
    alarm(1);
}

int main() {
    signal(SIGALRM, sig);
    alarm(1);
    while (1) {
        string s = "QUEUEUE";
    }
    return 0;
}