linux - C++ 64 bit file i/o gotchas -

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i found interesting bug when converting c++ app 32 64 bit linux. our filestore class implements saving/restoring structs to/from file. calls fopen() , fclose() before , after each operation except in 1 method. in (buggy) method on 32-bit platforms, can fseek() , fread() without error though file has been fclose()'d other methods. on 64-bit platform crashes every time on fread(). guess on 32-bit platform underlying file struct persists after fclose() can still accessed. have further info on why difference , other gotchas 64bit file i/o?

it sounds undefined behavior me. 64 bit vs 32 bit aspect of question red herring. compiler free erase home directory, or maybe file federal tax return in such circumstances.


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