c++ - boost mapped_file_sink append to the end of a file when file is not large enough -


मैं एक लॉगर लिखने के लिए boost :: iostreams :: mapped_file_sink का उपयोग करना चाहता हूं

मैं पहले एक मैप_फ़ाइल बनाऊँ जो 4KB है; जब फ़ाइल पूर्ण हो गई है और प्रोग्राम 4K + 1 बाइट लिखने की कोशिश कर रहा है, तो मैं मैप_फाइल_परम के आकार को बड़ा करता हूं, "उसी फाइल" को फिर से खोलता हूं, लेकिन मैप_परम.ऑफसेट = 4 केबी सेट करता हूं। तब मैं स्मृति में लिखता हूं जहां। डेटा () रिटर्न देता है।

अब समस्या ये है कि जब मैं 4K + 1 बाइट डेटा को 4K + 1 स्थिति में जोड़ना चाहता हूं, तो फ़ाइल का पिछला 4 केबी डेटा मिट जाता है! मेरे पास केवल फाइल में (4 के + 1) ^ वें डेटा है!

क्या कोई मेरी मदद कर सकता है?

[UPDATE]: नीचे मेरा कार्यक्रम है: 

  शून्य read_write_unidirection_example () {boost :: iostreams :: mapped_file_sink file_sink; बढ़ावा :: iostreams :: mapped_file_params param_sink; इंट ऑफ़सेट = 0; इंट पेज; Bool restart = सच; Param_sink.path = "result.log"; Param_sink.offset = 0; Param_sink.new_file_size = file_sink.alignment (); / * यह लिखने के लिए बाइट्स का आकार होना चाहिए! * / File_sink.open (param_sink); std :: अदालत के & lt; & lt; param_sink.new_file_size & lt; & lt; std :: endl; अगर (! File_sink.is_open ()) वापसी; (इंट आई = 0; आई & lt; 4000; i ++) के लिए {std :: stringstream ss; Ss & lt; & lt; "LOG ********" & lt; & lt; i & lt; "-" & lt; & lt; ऑफसेट & lt; & lt; "********* \ n"; Int slen = strlen (ss.str ()। C_str ());

मैं हर बार result.log फ़ाइल को जोड़ना चाहता हूं जब यह फ़ाइल फिर से खोल दी जाती है। Result.log को लॉग फ़ाइल के रूप में सेवा के लिए माना जाता है।


Comments

Post a Comment

Popular posts from this blog

scala - Play Framework - how to bind form to a session field -

Is there any way, I can get some parameters from the header, cookies (log in userId in my case) , And then apply it in a form which I know who will deposit the ticket? SupportForm supportForm: form [supportTicket] = form (mapping ("question" -> text, "priority" -> text) (apply support ticket. (HelpText.update) What are the good practices here? What is the call to apply the request, when I can use it (and also a good practice?) Edit An issue, absolutely deceiving anyone if I were to create a hidden area with this value. It could Ript, but the issue may be re-used in any way to verify and return the form, it can not be sure how it ....
Read more

c++ - Why does Visual Studio Release build break on non-executing code line -

When I created my C ++ program with the default release configuration in Visual Studio 10, I put a breakpoint on one line Who should never be reached. What confunded me was that when the program is running then it stopped at the breaking point. Adding a volatile statement and transferring this line to the break point does not break the execution of the code where the brake appears (though does not produce the same behavior as creating a minimum project with this function). Why is the "Release Debugger" (?) Step on this line and when executing breakpoints are executed? If I keep going after the break then false statement continues to return code execution. bool bounding box :: Cutting (int32_t xpos, int32_t ypos, int32_t dx, int32_t dy) const {int32_t intersectionX; Int32_t intersections; If ((dx> 0 & amp; amp; and & amp; xpos> rights) || (dx gt; Top) || (D & LT; 0 & amp; AOPO & Lt; BOT)) Return; If (DX! = 0) {intersection Y = ypos + (left...
Read more

Firefox reacting to JQuery setTimeout that doesn't apply -

& lt; - Only note the first image. I think some jquery is not working in Firefox, where there seems to be a problem ... but there is IE (I know, I know) var hover = $ ('# par1'), box = $ ('.sq1'); Hover.hover (function () {box.toggleClass ('index2');}); and var linkloc = $ ('# par1'), link = $ ('# frnt1'); Linkloc.on ('mouseenter', function () {function linkadd () {link.html ("& lt; a target = _blank href = http: //www.google.co.uk> & lt; img src = small1 .JPG / & gt; & lt; / a & gt; ");} Set Timeout (linkAD, 1500)}); Linkloc.on ('mouseleave', function () {link.html ("& lt; img src = small1.JPG />");}); I appreciate that the code can be a bit messy, but I'm still learning as I go. The problem now is that the top slice of the code is reacting down to the setout. (It revolves around time with setTimeout repeatedly) even though the name of the function is c...
Read more