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while trying to print map iterator value in gdb, I got following error:

(gdb) p map_it->first
operator-> konnte nicht gefunden werden. (English: operator-> could not be found.)
(gdb) p map_it->second.startVal
operator-> konnte nicht gefunden werden.
But the same expression can be used without any problem:
    while (map_it != lineData.end()) {
        colStart[map_it->first] = map_it->second.startVal;
        ++map_it;
I use gdb on Ubuntu: GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
How can this problem be avoided? Many thanks for any suggestion!
Weichao
                try building your app with debug symbols and -O0 (no optimization), then I think you can easily print it. It is probably getting inlined.
– fadedreamz
                Aug 21, 2022 at 7:32
                @fadedreamz Your suggestion solved my problem! Many thanks! Could you please explain what "getting inlined" means? Many thanks in advance!
– W. Wang
                Aug 23, 2022 at 17:13
                Its an optimization that compiler does to make the code execute faster. In a simplified world, the inlining process will generate code that actually put the address of map_it instead of generating a symbol (read a variable - map_it) for it. That makes the code executes a lot faster than it would've without any runtime penalty. So, when the inlining is happening, the map_it symbol may not be generated and thus gdb can not find anything named map_it when you are trying to print it. You can still print it, but it is a little bit involved process. Hope this helps.
– fadedreamz
                Aug 26, 2022 at 0:59
                @fadedreamz Many thanks again! You've help me out from the difficulty and understand the background. Thank you!
– W. Wang
                Aug 26, 2022 at 20:33
        
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