Uli is the real expert here, so I may be a little off.
I came across a library `libexiv2.so'(www.exiv2.org) which has some hidden symbols in it. But the `Version symbol' entries for those hidden symbols are shown as - 1 *global* - by `eu-readelf -sV'. Now if symbol is hidden
- shouldn't the highest(15'th) bit of the corresponding `Version symbol' entry be set? And if so, then it could not possibly equate to 1, right?
I don't know that ST_VISIBILITY bits relate to version sets in this way.
a binary(say tcpdump) is linked to a library(libpcap) which does not use Symbol Versioning and does not have `Version definition' section in it. In such a case,
$ `eu-readelf -sV tcpdump'
shows an output wherein, `Version symbol' entries for symbols defined in libpacp are shown as: 0 *local* . Which means the symbol is defined in the same object and is not accessible outside of the same, right?
No. These are undefined symbols in tcpdump. The 0 indicates lack of a version binding for the symbol.
- `Version symbol' entries are greater than 1 if and only if the concerned library(or DSO) uses symbol versioning.
I think this is correct.
- And if so, there is no way of knowing if a *local* symbol is defined in the same object/binary or is resolved from a library while running?
SHN_UNDEF symbols always have to be resolved.