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clibunwind

What means (3) in fnc(3)?

Looking libunwind.h docs(https://www.nongnu.org/libunwind/docs.html),

All functions(ex.libunwind-ia64(3), unw_get_proc_name(3)) have fnc name + (3). What means (3)?

Solution

  • The number refers to the section in the Linux manual that the documentation for these functions reside in.

    When using the man command to look up documentation you can optionally specify the section, for example man unw_get_proc_name or man 3 unw_get_proc_name. You would need to specify the section if there was a manual entry with that name in a different section.

    This practice goes back to the UNIX days. I've personally seen it going back to Solaris 2.5.1 (1994-1995), but it's probably older than that.