Question

If I create a SM from 64 bit application and open it on 32 bit application it fails.

//for 64 bit
    shared_memory_object( create_only, "test" , read_write) ; 
// for 32 bit
    shared_memory_object (open_only, "test", read_write);

file created by 64bit application is at path as below:

/private/tmp/boost_interprocess/AD21A54E000000000000000000000000/test

where as file searched by 32 bit application is at path

/private/tmp/boost_interprocess/AD21A54E00000000/test

Thus 32 bit applications cannot read the file.

I am using boost 1.47.0 on Mac OS X.
Is it a bug? Do I have to do some settings use some Macros in order to fix it? Has any one encountered this problem before?

Answer 1

I found the solution to the problem and as expected it is a bug.

This Bug is present in tmp_dir_helpers.hpp file.

    inline void get_bootstamp(std::string &s, bool add = false)
    {
      ...
       std::size_t char_counter = 0;
       long  fields[2] = { result.tv_sec, result.tv_usec };
       for(std::size_t field = 0; field != 2; ++field){
          for(std::size_t i = 0; i != sizeof(long); ++i){
             const char *ptr = (const char *)&fields[field];
             bootstamp_str[char_counter++] = Characters[(ptr[i]&0xF0)>>4];
             bootstamp_str[char_counter++] = Characters[(ptr[i]&0x0F)];
          }
       ...
    }

Where as it should have been some thing like this..

**long long** fields[2] = { result.tv_sec, result.tv_usec };
           for(std::size_t field = 0; field != 2; ++field){
              for(std::size_t i = 0; i != sizeof(**long long**); ++i)

I have created a ticket in boost for this bug.

Thank you.