Re: malloc(0) during exception throw & catch

[Denis Perchine <dyp at perchine dot com>]

> > And all memory races detection tools says that there is call of
> > malloc(0) inside it.
> 
> Thanks for your bug report. You did not mention what platform you are
> using, so it is hard to reproduce the problem. I could not reproduce
> it on i586-pc-linux-gnu, with gcc 2.95.2.

gcc-2.95.2. i686-linux. 2.2.15.

Exception SHOULD be derived from exception.

#include <stdio.h>
#include <exception>

class ex : public exception {
public:
  ex() : exception() {};
};

int main() {
  try {
    throw ex();
  } catch (ex &x) {
    fprintf(stderr, "ex catched\n");
  }

  return 0;
}

Compile it with -g option (this is obligatory. Somehow without debug info all is OK).
And use for example YAMD (http://www3.hmc.edu/~neldredge/yamd/)

run-yamd -l 2 -o a ./ex

And you will get:

YAMD version 0.32
Starting run: ./ex
Executable: /home/dyp/tmp/throw/ex
Virtual program size is 1472 K
Time is Sun May 28 06:10:27 2000

default_alignment = 1
min_log_level = 2
repair_corrupted = 0
die_on_corrupted = 1
check_front = 0

WARNING: Zero-byte allocation
Address 0x2ac23000, size 0
Allocated by malloc at
        /lib/libc.so.6(malloc+0x2e)[0x2ab88ede]
        /usr/lib/libstdc++-libc6.1-2.so.3(_._13bad_exception+0x46e)[0x2ab04b92]
        /usr/lib/libstdc++-libc6.1-2.so.3(_._13bad_exception+0x574)[0x2ab04c98]
        /usr/lib/libstdc++-libc6.1-2.so.3(__frame_state_for+0x23)[0x2ab05497]
        /usr/lib/libstdc++-libc6.1-2.so.3(__throw+0x67)[0x2ab03bef]
        /home/dyp/tmp/throw/ex.cpp:12(main)[0x8048943]
        /lib/libc.so.6(__libc_start_main+0x115)[0x2ab4fd69]
        ??:0(_start)[0x8048811]

WARNING: Zero-byte allocation
Address 0x2ac25000, size 0
Allocated by malloc at
        /lib/libc.so.6(malloc+0x2e)[0x2ab88ede]
        /usr/lib/libstdc++-libc6.1-2.so.3(_._13bad_exception+0x47a)[0x2ab04b9e]
        /usr/lib/libstdc++-libc6.1-2.so.3(_._13bad_exception+0x574)[0x2ab04c98]
        /usr/lib/libstdc++-libc6.1-2.so.3(__frame_state_for+0x23)[0x2ab05497]
        /usr/lib/libstdc++-libc6.1-2.so.3(__throw+0x67)[0x2ab03bef]
        /home/dyp/tmp/throw/ex.cpp:12(main)[0x8048943]
        /lib/libc.so.6(__libc_start_main+0x115)[0x2ab4fd69]
        ??:0(_start)[0x8048811]

*** Finished at Sun May 28 06:10:27 2000
Allocated a grand total of 9104 bytes
8 allocations
Average of 1138 bytes per allocation
Max bytes allocated at one time: 9080
96 K alloced internally / 64 K mapped now / 36 K max
Virtual program size is 1588 K
End.

-- 
Sincerely Yours,
Denis Perchine

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