Hello,
I came across an interesting behavior that is IMO worth sharing with other developers. It turns out that fmemopen() fails with error 22 EINVAL if the buffer passed in is of length 0.
Imagine situation: I have a file in the directory of 0 length. I open it with fopen() or with open() and then fdopen() in "r" mode and I can read it with getline(). Of cause the first read will return EOF and I will be done. But if I open file with open() in binary mode, and mirror it into a buffer and the file is of length 0 then the buffer will be of length 0 too but attemt to use fmemopen() would fail. So mirroring in becomes non transparent operation you have to special case the situation when original file in NULL.
So question is what should I do with it? File a bug or just ask to document it? Man page does not say anything about it. Advises welcome.