Running the app with custom downloaded glibc gives seg fault

Question

I downloaded custom glibc and then compiled using g++ dt.cpp -std=c++11 -Wl,-rpath "/opt/glibc-2.28/lib", but it gives seg fault

#include <iostream>                                                                                                                                                                    
#include <ctime>                                                                                                                                                                       
                                                                                                                                                                                       
int main()                                                                                                                                                                             
{                                                                                                                                                                                      
  std::tm tm = {};                                                                                                                                                                     
  char* result = strptime ("2024-11-07", "%Y-%m-%d", &tm);                                                                                                                             
                                                                                                                                                                                       
  if(result)                                                                                                                                                                           
  printf("Result: *%d*\n", tm.tm_mday);                                                                                                                                                
                                                                                                                                                                                       
  time_t time_ = std::mktime (&tm);                                                                                                                                                    
  std::cout << "mytime: " << time_ << std::endl;                                                                                                                                       
}   

ldd for the binary gives the following

      linux-vdso.so.1 (0x00007ffc073f9000)
        libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f85cda5e000)
        libc.so.6 => /opt/glibc-2.28/lib/libc.so.6 (0x00007f85cd6a7000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f85cd309000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f85ce0c1000)
        libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f85cd0e6000)

Answer 1

but it gives seg fault

That is expected, because you are mixing the dynamic loader /lib64/ld-linux-x86-64.so.2 with an incompatible /opt/glibc-2.28/lib/libc.so.6.

See also this answer for a solution.