In case anyone is interested... Turns out that my original code intended to detect permissions errors in a cross platform way did not work on Windows. The comparison has to be performed on the exception's error_code, not the error_code's value. The value seems to be platform specific. So the correct (I think) cross platform solution for detecting a permissions error is as follows: if (boost::system::posix_error::permission_denied == e.code()) { std::cout << "The error code indicates a permissions error, as expected. " << std::endl; } Note the absence of the ".value()" in the comparison. Best, -- Allen Cronce On Aug 10, 2008, at 9:31 AM, Allen Cronce wrote:

Hi all,

I need to programmatically test for permissions errors during path iteration. I think what I need to do is catch the filesystem exception, then drill out the error code and compare it to the permission_denied error value.

Here's a code fragment written under boost 1.35 that demonstrates what I'm talking about:

try { // Force a permissions error on *nix machines when not running as root. // Note that this code is is for demonstration purposes only. Assume that // in the real implementation I'm doing something else here with the // filesystem that *might* throw a permissions error. boost::filesystem::path testDirPath( "/usr/local/cant_touch_this" ); create_directory(testDirPath); } catch(const boost::filesystem::filesystem_error& e) { // Check the error code to see if it's a permissions error if (boost::system::posix_error::permission_denied == e.code().value()) { std::cout << "The error code indicates a permissions error, as expected. " << std::endl; } else { std::cout << "Hmm... I didn't get a permissions error. That's wrong." << std::endl; } }

Is this basically the right approach?

Note that one concern I have is maintainability. A coworker wrote similar code to the above, but under boost 1.33.1. That code broke under 1.35 due to significant changes to the filesystem exceptions mechanism.

I understand that there are no guarantees moving forward to new boost versions. I knew the job was dangerous when I took it ;-) But if there's anything I can do today to future-proof a little bit, that would be great.

Thanks in advance for any feedback or suggestions.

Best, -- Allen Cronce