829 questions
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ValueError: the greenlet library is required to use this function. libstdc++.so.6: cannot open shared object file: No such file or directory
Command that I ran in python virtual environment of my project:
POSTGRES_USER=admin POSTGRES_PASSWORD=admin POSTGRES_HOST=localhost POSTGRES_DB=postgres alembic revision --autogenerate -m "add ...
- 199
1
vote
1
answer
64
views
Why is libc++ not a dynamic executable like libstdc++?
I stumbled across this when building clang and gcc from source. libstdc++ seems to be dynamically linked while libc++ is not. Why is this the case? Does it mean libc++ has glibc and glib statically ...
- 5,018
1
vote
1
answer
66
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Conda environment does not isolate each environment
I am trying to install some packages upon newly created conda environment. But weirdly it is already full of packages, which have been used in other previous conda environments. For example, I noticed ...
1
vote
1
answer
102
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R Package Installation Failure on Pop!_OS 22.04: GLIBCXX/GLIBC Version Mismatch (readr, googlesheets4)
I'm getting dependency errors when I try to install R packages readr and googlesheets4 on my Pop!_OS 22.04 system. This is particularly problematic because readr is a core dependency of the tidyverse ...
-1
votes
2
answers
110
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Problem when porting a program compiled using a new compiler
On the CentOS 7.5 operating system, the gcc compiler version 13.3 was built from the source code. Using this compiler, the test program was built
g++ main.cc -std=c++20
After the build, the program ...
- 307
1
vote
0
answers
579
views
`GLIBCXX_3.4.32' not found: update libstdc++ or rebuild toolchain?
I have compiled my-very-own cross-toolchain with ct-ng.
I used the most recent GCC:
$ aarch64-myown-linux-gnu-g++ (crosstool-NG 1.27.0_rc1.1_0842e65 - MyOwn Toolchain Builder v1.0) 14.2.0
Copyright (C)...
- 2,632
5
votes
1
answer
165
views
Why does Clang think that std::unique_ptr is not standard-layout?
I have the following assertion:
#include <memory>
#include <type_traits>
static_assert(std::is_standard_layout_v<std::unique_ptr<int>>);
This assertion passes on GCC, but ...
- 41.1k
2
votes
1
answer
73
views
How to pick top k elements from std::map
I have a std::map with uint32_t as the key type and a custom value type. I want to pick out the top k key value pairs from this map based on the members of the value type. To do this, I'm first ...
- 1,018
2
votes
0
answers
140
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Why does std::vector::shrink_to_fit() have no effect when exceptions are disabled?
When compiling using gcc 14.2 (or Clang), std::vector::shrink_to_fit() has no effect when exceptions are disabled. This can be demonstrated through the following code (Live on Compiler Explorer):
#...
- 1,998
0
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66
views
What's the differance of UnformattedInputFunction implementation between libstdc++ and libc++?
I'm manipulating raw input of keyboard in std c++.
The code working with libstdc++ but libc++.
When UP arrow key stroked,
get 1b 5b 41 output if compiled with g++ -std=c++23 rawkey.cpp or clang++ -...
- 387
7
votes
3
answers
362
views
How to make C++ be as economical with memory as C, while still using STL?
These C and C++ programs are equivalent (as I'm using -fno-exceptions, below):
"loop.c":
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
const int N = 1024 * 4;
...
- 12.6k
1
vote
1
answer
125
views
What does this constructor basic_string<decltype(nullptr)>(char const*) do?
Recently i was reading some assembly codes of aarch64, and i found this strange constructor which seems not defined in the basic_string:
...
- 13
1
vote
0
answers
83
views
How to add a few missing std:: functions from libstc++6?
I'm compiling a c++ application on a very old system with libstdc++6. This libstdc++6 has functions up to GLIBCXX_3.4.21.
I need to use an external .so library which uses just a few more functions up ...
- 1,927
0
votes
0
answers
95
views
Enable runtime UB checks in libstdc++
Is it possible with g++/libstdc++ to enable runtime UB checks, so that for example:
std::vector::operator[] behaves the same as std::vector::at()
std::optional::operator* behaves the same as std::...
- 97.6k
0
votes
1
answer
44
views
Building GCC found no GLIBCXX in libstdc++.so
I am now building GCC 12.1.0 on CentOS 7.4, and I'm surprisingly find that there are no GLIBCXX at all in the built libstdc++.so.6. However, older version like 5.5.0, 7.4.0 and 9.3.0 would not run ...
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