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1. nikhedonia commented on Oct 11, 2017

   

   nikhedonia

   on Oct 11, 2017

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   @odinthenerd good point. We probably need to align to the next power of two. Would be nice if someone could write a testcase for ARM as it does not support unaligned memory
2. jcelerier commented on Dec 31, 2017

   

   jcelerier

   on Dec 31, 2017

   Last edited by jcelerier

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   hi, I've forked this for my own uses (and ended up rewriting most of it anyways :p ) ; for the alignment issue I've used the C++ alignas / alignof operator and passed the alignment as a template parameter ; that way, it can be checked at compile time just like the size (and can be tweaked by the user if necessary):

   https://github.com/jcelerier/smallfunction/blob/master/smallfun/include/smallfun.hpp

   👍React with 👍1Reacted by Odin Holmes
3. nikhedonia commented on Jan 4, 2018

   

   nikhedonia

   on Jan 4, 2018

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   @jcelerier could we use std::allign and std::alligment_of to accomplish proper alignment?
   Do you know in which cases the alignment needs to be adjusted?
4. jcelerier commented on Jan 4, 2018

   

   jcelerier

   on Jan 4, 2018

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   Do you know in which cases the alignment needs to be adjusted?

   well, in a lot of cases :p for instance pointers have to be aligned on a pointer size at least.

   eg:

   int main()
   {
     int x = 0;
   
     struct
     {
       bool some_bool;
       smallfun::SmallFun<int()> fun;
     } b;
   
     b.fun = [&x] { return x; };
     return b.fun();
   }

   compile:

    $ g++ -fsanitize=undefined align_test.cpp && ./a.out
   

   results in

   align_test.cpp:95:31: runtime error: member call on misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:95:31: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:95:31: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:36:19: runtime error: member call on misaligned address 0x7ffee196a3b9 for type 'struct __lambda0', which requires 8 byte alignment
   0x7ffee196a3b9: note: pointer points here
    98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:123:16: runtime error: member access within misaligned address 0x7ffee196a3b9 for type 'const struct __lambda0', which requires 8 byte alignment
   0x7ffee196a3b9: note: pointer points here
    98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:89:7: runtime error: member call on misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:89:7: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:89:7: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct concept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:39:23: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct SFModel', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:39:23: runtime error: member call on misaligned address 0x7ffee196a3b1 for type 'struct SFConcept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:39:23: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct SFConcept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:15:25: runtime error: member access within misaligned address 0x7ffee196a3b1 for type 'struct SFConcept', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 90 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:15:25: runtime error: reference binding to misaligned address 0x7ffee196a3b1 for type 'struct <unknown>', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 f0 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00
                 ^ 
   align_test.cpp:39:23: runtime error: reference binding to misaligned address 0x7ffee196a3b1 for type 'struct <unknown>', which requires 8 byte alignment
   0x7ffee196a3b1: note: pointer points here
    00 00 00  00 f0 9c 9a 52 98 55 00  00 70 a2 96 e1 fe 7f 00  00 02 00 00 00 00 00 00  00 00 00 00 00