I might be wrong, but I'm reasonably sure that you link to the system call's man page. Which is probably what the tool in question uses, but .. not the same thing.

Elsewhere in this discussion: There's a difference between man page section 1 and 2 - and read was quoted as an example for a potential ambiguous result if you invoke "man read" (opens man 1 read here, when man 2 read was the syscall I might want to look at after running strace).

His blog is here: http://crtags.blogspot.com/2013/12/ptrace-now-available.html