eld Manual

Binding of References
eld Manual—527255-009
3-24
Finding and Reading The Public DLL Registry
(ZREG) File
2. If the -public_registry option is not specified then the linker looks for a file named
zreg in its own directory or subvolume. If this location is a \bin or /bin, eld will also
look in a corresponding \lib or /lib location. This supports the practice, on PCs and
OSS, of putting eld in a bin directory and the public DLLs (together with the zreg
file) in a sibling lib directory.
On OSS, where case is significant, zreg is lower case. If the file exists and the
linker can open it for reading, this file is deemed to be the public registry file.
Otherwise, if the -nostdlib option has not been specified, the linker writes out a
warning message.
3. If still not found, and the host platform is TNS/E, the linker uses a system call
(pubLibSpecs_get_) to find the location of the zreg file.
If the linker finds the public DLL registry, it then determines a list of public DLL
filenames. This information is used elsewhere in the linker for two purposes.
First, it is used to locate public DLLs, as discussed in Finding Public DLLs on
page 2-18. Second, it is used to locate the import library that represents the implicit
libraries, as discussed in Presetting Loadfiles on page 3-5.
As explained in those two sections, a filename found within the public DLL registry file
may be used by the linker to search for a file on a platform where filenames are case
sensitive. In that case, the linker will interpret what it finds within the public DLL registry
to be lower case. So, to avoid confusion, it is strongly recommended that all filenames
mentioned in the public DLL registry be written in lower case, and that when
corresponding files exist on a platform where case is significant those files are given
lower case filenames, and furthermore that the DLL names found within such files are
also written in lower case.