Hi, I read parts of Drepper's [0] and Oliva's [1] work on TLS access. From my understanding, the `initial-exec' model can be used safely when compiling an executable. However, it's still unclear to me whether/when it can be used within a shared library. Section 3 of [0] explains `initial-exec' like this: A more restrictive optimization is usable if the variables accessed are known to be in one of the modules available and program start and if the programmer selects to use the static access model. I believe it should read "available *at* program start". Likewise, Section 2.1 of [1] reads: Under certain circumstances, [the Initial Exec model] may be used in dynamic libraries as well, but it may come at the cost of being unable to dlopen such libraries. This gives the impression that shared libraries that are not meant to be dlopened can be compiled with `-ftls-model=initial-exec'. Is this true? If so, would using `-ftls-model=initial-exec' cause problems with the way the shared library accesses other library's TLS (e.g., libc's `errno')? IOW, instead of using `-ftls-model', should one instead use an explicit `tls_model' attribute for all the library's thread-local variables? Thanks, Ludovic. [0] http://people.redhat.com/drepper/tls.pdf [1] http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/paper.pdf
