SHMOP (SYSV) returns -1 on error

[Doug Gwyn <gwyn>]

> I thought that every SYSTEM CALL returned -1 on error. For example, read
> returns -1 if you give it a fid that hasn't been opened, is not readable etc.
> EOF is NOT considered an error, and is signalled by a 0 return. Thus SHMOP
> returning -1 on an error would be consistent with all other system calls.

So tell me, what does that mean for a (char *)-valued function?