Hello, We have a huge client/server application, mostly written in C. We moved now with it for the first time to 64-bit Linux (SuSE SLES 12 x86_64) and compiled with gcc 4.9.2, but with -m32 (because we have to support also 32-bit customers). The historical (20++ years) grown code was full of memcpy(3) calls, sometimes for overlapping memory, which is prohibited by the man page of memcpy(3), of course, and we got what we deserve: corrupted memory in destination of the copy. We nailed it down, substituted memcpy(3) by memmove(3) and all is fine. What me motivates to this posting is: Why the (wrong) usage of memcpy(3) did not showed up on SLES 11 and/or 32bit? What is the exact problem with memcpy(3) prohibiting the overlapping memory,? And, last but not least: Why we have memcpy(3) at all, if memmove(3) gives the same result and is thread-safe too? For example, on my beloved FreeBSD memcpy(3) is implemented as bcopy(3), I checked the code for it, and allows even overlapping memory. Thx matthias -- Matthias Apitz, ✉ guru@xxxxxxxxxxx, ⌂ http://www.unixarea.de/ ☎ +49-176-38902045
