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</o:shapelayout></xml><![endif]--></head><body lang=DE link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hey,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>I want to implement file output for a rendering application and want to use C++ file streams using the following callback write function:<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> cairo_status_t cairo_write_func (<span style='color:blue'>void</span> *closure, <span style='color:blue'>const</span> <span style='color:blue'>unsigned</span> <span style='color:blue'>char</span> *data, <span style='color:blue'>unsigned</span> <span style='color:blue'>int</span> length)<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> {<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>try</span><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> {<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>const</span> std::string s(data, length);<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> fout << s;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> fout.flush();<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> }<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>catch</span> (std::exception &e)<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> {<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>return</span> CAIRO_STATUS_WRITE_ERROR;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:9.5pt;font-family:Consolas'> </span><span style='font-size:9.5pt;font-family:Consolas'>}<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.5pt;font-family:Consolas'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.5pt;font-family:Consolas'> <span style='color:blue'>return</span> CAIRO_STATUS_SUCCESS;<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:9.5pt;font-family:Consolas'> }<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I just can’t figure out what the closure is for.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Can anyone explain the concept to me?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Is it comparable to variable capturing in C++11 closures?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Could I just pass nullptr as I do not use it anyway?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Thanks,<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>--</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>David Weiß</span><span lang=EN-US style='font-size:10.0pt;color:#E02129;mso-fareast-language:DE'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:#E02129;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:#E02129;mso-fareast-language:DE'>PTV GROUP</span><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'>Logistics Software Development<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;color:black;mso-fareast-language:DE'>Haid-und-Neu-Str. 15, 76131 Karlsruhe, Germany<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;mso-fareast-language:DE'><a href="mailto:david.weiss@ptvgroup.com"><span style='color:windowtext;text-decoration:none'>david.weiss</span><span style='color:windowtext;text-decoration:none'>@ptvgroup.com</span></a></span><span style='font-size:10.0pt;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:10.0pt;mso-fareast-language:DE'><a href="http://www.ptvgroup.com/"><span lang=DE style='color:windowtext;text-decoration:none'>www.ptvgroup.com</span></a></span><span style='font-size:10.0pt;mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:10.0pt;mso-fareast-language:DE'>http://ptv.to/facebook<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:7.0pt;color:black;mso-fareast-language:DE'><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:7.0pt;color:black;mso-fareast-language:DE'>PTV Planung Transport Verkehr AG<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Headquarters: Karlsruhe<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Executive Board: Vincent Kobesen (CEO)<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Chairman of the Supervisory Board: Dr. h.c. Frank-Jürgen Weise<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Commercial Register (HRB-Nr): 109262<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:7.0pt;color:black;mso-fareast-language:DE'>Local Court: Mannheim</span><span lang=EN-US style='mso-fareast-language:DE'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></body></html>