ExifTool Forum

Hi,

When I compile cpp_exiftool with gcc 8.1.1 with -Wall -Werror flags (on Linux), I get this error (without the -Werror flag, it's just a warning):

cpp_exiftool/inc/ExifTool.h:84:19: error: 'ExifTool::mCmdQueueSize' will be initialized after [-Werror=reorder]
int           mCmdQueueSize;// size of command queue

This is because the member 'mWatchdog' is positioned differently in the ExifTool member initialization list (in the cpp file) compared to the member declarations in the header. Moving the declaration in the header file fixes the problem (see patch below).

Is this a modification that could be considered for inclusion in the official code release?

Thanks for reading!


*** ExifTool_original.h 2018-07-24 13:13:15.363888877 +0200
--- ExifTool.h 2018-07-24 13:13:20.044173569 +0200
***************
*** 77,87 ****
      ExifToolPipe  mStderr;      // buffer for exiftool stderr read pipe
      int           mTo;          // write pipe for exiftool stdin
      int           mPid;         // exiftool application process ID
-     int           mWatchdog;    // watchdog process ID
      TagInfo     * mWriteInfo;   // tag information to write
      char        * mCmdQueue;    // queued command arguments (NULL if nothing queued)
      int           mCmdQueueLen; // length of data in command queue
      int           mCmdQueueSize;// size of command queue
      int           mLastComplete;// result of last Complete() call
      int           mCmdNum;      // last command number
  };
--- 77,87 ----
      ExifToolPipe  mStderr;      // buffer for exiftool stderr read pipe
      int           mTo;          // write pipe for exiftool stdin
      int           mPid;         // exiftool application process ID
      TagInfo     * mWriteInfo;   // tag information to write
      char        * mCmdQueue;    // queued command arguments (NULL if nothing queued)
      int           mCmdQueueLen; // length of data in command queue
      int           mCmdQueueSize;// size of command queue
+     int           mWatchdog;    // watchdog process ID
      int           mLastComplete;// result of last Complete() call
      int           mCmdNum;      // last command number
  };


Thanks for letting me know about this.

I hate the C++ compiler.

I would rather change the initialization than the order of the class members.  How about this?:

===================================================================
RCS file: /Users/phil/cvs/exiftool2/cpp_exiftool/src/ExifTool.cpp,v
retrieving revision 1.30
diff -r1.30 ExifTool.cpp
122,123c122,123
<         : mWriteInfo(NULL), mCmdQueue(NULL), mCmdQueueLen(0), mCmdQueueSize(0),
<           mWatchdog(-1), mLastComplete(0), mCmdNum(0)
---
>         : mWatchdog(-1), mWriteInfo(NULL), mCmdQueue(NULL), mCmdQueueLen(0),
>           mCmdQueueSize(0), mLastComplete(0), mCmdNum(0)

- Phil

Looks good to me! I wasn't sure which fix you would prefer, but your version is perhaps safer since it doesn't mess with memory layout, like mine did.

Thanks for your attention and the great tool you've created.

Thanks.

I've updated the web page (http://owl.phy.queensu.ca/~phil/cpp_exiftool/) with the new version.

- Phil