| Title: | DIGITAL UNIX (FORMERLY KNOWN AS DEC OSF/1) |
| Notice: | Welcome to the Digital UNIX Conference |
| Moderator: | SMURF::DENHAM |
| Created: | Thu Mar 16 1995 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 10068 |
| Total number of notes: | 35879 |
I am having a problem with forcing the unload of a shared library. The libary loads fine using dlopen, and unloads fine - provided that I never call anything in it (no surprise here). However, if I have called a function in the library, the dlclose appears to succeed (no error reported through dlerror), but the libary has not unloaded. I am checking what modules are loaded by using ldr_next_module/ldr_inq_module. Unfortunately, I need to force an unload of the shared object so that I can and reload it cleanly. The reason for needing to do this is unpleasant, basically around forcing a clean restart of the Micro Focus runtime, and has worked on other platforms. This is on Digital UNIX V4.0a. Any suggestions ? -gerry
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 9157.1 | VAXCPU::michaud | Jeff Michaud - ObjectBroker | Thu Mar 13 1997 10:54 | 15 | |
I believe shared libs loaded into your process are reference counted. So if someone in your process has done a dlopen (either explicitly, or implicitly by being linked against the shared lib, or a shared lib that is linked against the shared lib, etc etc), subsequent dlopen's of a shared lib already loaded simply increment a reference count. And the reference happens when with dlclose, it decrements the reference count and only if it's zero does the library really get unloaded (otherwise you would pull the rug out from under somebody else in your process). You could try to force the shared lib to be unloaded by making multiple calls to dlclose, but this is risky as you are likely pulling the rug out from somebody else in your process ... | |||||
| 9157.2 | I'll try multiple dlclose calls.. | MUFFIT::gerry | Gerry Reilly | Thu Mar 13 1997 11:04 | 6 |
Thanks. I'll actually try multiple dlclose calls. I know who the somebody else is (I know it isn't my code!) and I probably don't care about pulling the rug as I know they (the somebody else) is never going to get called again. -gerry | |||||
| 9157.3 | SMURF::LOWELL | Fri Mar 28 1997 09:51 | 18 | ||
Gerry, dlopen keeps two counts. The first is the number of times dlopen is called for that library, and the second is the number of other libraries that reference that library as a dependency. Whether you call something in the library shouldn't make any difference as to whether it can be closed or not. (Unless of course, you call something that results in another dlopen of that library or something that references that library.) Please submit a QAR, with test case if possible, otherwise include the dependency lists (odump -Dl) of all of the shared libs used by the program and note which ones are dynamically loaded. Thanks, Randy | |||||
| 9157.4 | QAR 52310 | MUFFIT::gerry | Gerry Reilly | Thu Apr 03 1997 08:45 | 5 |
QAR 52310 Thanks for the help. -gerry | |||||