> From: Dr. Stephen Henson [mailto:st...@openssl.org] > Sent: Tuesday, January 28, 2014 6:41 PM > On Tue, Jan 28, 2014, Adam M wrote: > > > Hi, > > > > I'm reading the documentation for ERR_get_error_line_data() here: > > http://www.openssl.org/docs/crypto/ERR_get_error.html > > > > The comments say that 'data' is dynamically allocated with > > OPENSSL_malloc() if the ERR_TXT_MALLOCED bit is set in 'flags'. I > > presume this means that we need to call OPENSSL_free() to free > 'data', > > but the documentation isn't clear on that. > > > > I'm running into two issues in this regard. For one, 'data' is a > 'const > > char*', but OPENSSL_free() takes a 'void*', so we get a type > mismatch. > > See my sample code here, which includes the compiler error message: > > http://pastebin.com/VNdkwf0G > > > > The second issue is that I've been looking around on the web (in > > particular on Ohloh) for usage of ERR_get_error_line_data(), and no > one > > seems to be checking for the ERR_TXT_MALLOCED bit in 'flags'. Maybe > > doing so isn't necessary, but the documentation seems to suggest that > it > > is. > > > > Can someone please help clarify what exactly to do here? > > > > You can see and example of how it is used internally in the library in > crypto/err/err_prn.c all you need to check is that ERR_TXT_STRING is > set. The > flag ERR_TXT_MALLOCED is an internal flag which indicates whether the > string > should be freed when the error queue is emptied: applications must not > free the > string themselves. > > Steve.
Surely ERR_get_error_line_data() passes ownership of the data to the caller, and removes it from the error queue? How would the library know to free it subsequently? I remember analyzing the source in some detail a while ago when I was wondering the same as Adam, and that's the conclusion I came to at least. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
