Questions tagged [portability]
Portable code can be run with little to no modification in multiple environments. Portable applications can be run from e.g. a USB drive without modifying a computer's environment.
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What is the meaning of "POSIX"?
What exactly is POSIX? I have read the Wikipedia article but I still don't understand.
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answers
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How do SO_REUSEADDR and SO_REUSEPORT differ?
The man pages and programmer documentations for the socket options SO_REUSEADDR and SO_REUSEPORT are different for different operating systems and often highly confusing. Some operating systems don't ...
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Is there a portable way to get the current username in Python?
What is a portable way (e.g. for Linux and Windows) to get the current user's username? Something similar to os.getuid() would be nice:
>>> os.getuid()
42
# Does not currently exist in ...
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votes
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Why should I not #include <bits/stdc++.h>?
I posted a question with my code whose only #include directive was the following:
#include <bits/stdc++.h>
My teacher told me to do this, but in the comments section I was informed that I ...
306
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9
answers
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Why does glibc's strlen need to be so complicated to run quickly?
I was looking through the strlen code here and I was wondering if the optimizations used in the code are really needed? For example, why wouldn't something like the following work equally good or ...
user11954200
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votes
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answers
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Is there a replacement for unistd.h for Windows (Visual C)?
I'm porting a relatively simple console program written for Unix to the Windows platform (Visual C++ 8.0). All the source files include "unistd.h", which doesn't exist. Removing it, I get ...
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181
votes
10
answers
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OS specific instructions in CMAKE: How to?
I am a beginner to CMAKE. Below is a simple cmake file which works well in mingw environment windows. The problem is clearly with target_link_libraries() function of CMAKE where I am linking ...
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votes
7
answers
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How can I mark a C++ class method as deprecated?
I have a method in a C++ interface that I want to deprecate, with portable code.
When I Googled for this all I got was a Microsoft specific solution; #pragma deprecated and __declspec(deprecated).
If ...
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votes
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answers
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How should I print types like off_t and size_t?
I'm trying to print types like off_t and size_t. What is the correct placeholder for printf() that is portable?
Or is there a completely different way to print those variables?
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votes
9
answers
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How to measure time in milliseconds using ANSI C?
Using only ANSI C, is there any way to measure time with milliseconds precision or more? I was browsing time.h but I only found second precision functions.
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What belongs in an educational tool to demonstrate the unwarranted assumptions people make in C/C++?
I'd like to prepare a little educational tool for SO which should help beginners (and intermediate) programmers to recognize and challenge their unwarranted assumptions in C, C++ and their platforms.
...
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How to bundle a JRE with Launch4j?
I have Launch4J on my computer and it's a great program. One of its features I'm interested in is the ability to bundle a JRE in the general .EXE file. However, I can't find any documentation that ...
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votes
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answers
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Are the experimental features of modern C++ reliable for long-term projects?
I have a project that currently uses C++11/14, but it requires something like std::filesystem, which is only available in C++17, and hence I don't have a chance to currently use it. I see, however, ...
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votes
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answers
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How can I portably call a C++ function that takes a char** on some platforms and a const char** on others?
On my Linux (and OS X) machines, the iconv() function has this prototype:
size_t iconv (iconv_t, char **inbuf...
while on FreeBSD it looks like this:
size_t iconv (iconv_t, const char **inbuf...
I ...
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votes
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answers
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Is there a portable equivalent to DebugBreak()/__debugbreak?
In MSVC, DebugBreak() or __debugbreak cause a debugger to break. On x86 it is equivalent to writing "_asm int 3", on x64 it is something different. When compiling with gcc (or any other standard ...
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How to Declare a 32-bit Integer in C
What's the best way to declare an integer type which is always 4 byte on any platforms? I don't worry about certain device or old machines which has 16-bit int.
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Is char *envp[] as a third argument to main() portable [duplicate]
In order to get an environment variable in a C program, one could use the following:
getenv()
extern char **environ;
But other than the above mentioned, is using char *envp[] as a third argument ...
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83
votes
6
answers
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views
Portable way of setting std::thread priority in C++11
What is the correct way in the post C++11 world for setting the priority of an instance of std::thread
Is there a portable way of doing this that works at least in Windows and POSIX (Linux) ...
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votes
17
answers
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views
Django: 'current_tags' is not a valid tag library
I have a small Django project I received from a friend. The code works perfectly on his system. However, on my system I get the following error message when running the server:
TemplateSyntaxError at ...
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votes
4
answers
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How do I type a floating point infinity literal in python
How do I type a floating point infinity literal in python?
I have heard
inf = float('inf')
is non portable. Thus, I have had the following recommended:
inf = 1e400
Is either of these standard,...
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78
votes
8
answers
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Why bit endianness is an issue in bitfields?
Any portable code that uses bitfields seems to distinguish between little- and big-endian platforms. See the declaration of struct iphdr in linux kernel for an example of such code. I fail to ...
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Is there any "standard" htonl-like function for 64 bits integers in C++?
I'm working on an implementation of the memcache protocol which, at some points, uses 64 bits integer values. These values must be stored in "network byte order".
I wish there was some uint64_t ...
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votes
7
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Using Python's ftplib to get a directory listing, portably
You can use ftplib for full FTP support in Python. However the preferred way of getting a directory listing is:
# File: ftplib-example-1.py
import ftplib
ftp = ftplib.FTP("www.python.org")
ftp....
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69
votes
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answer
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views
Proper shebang for Python script
I'm usually using the following shebang declaration in my Python scripts:
#!/usr/bin/python
Recently, I've came across this shebang declaration:
#!/usr/bin/env python
In the script documentation, ...
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67
votes
3
answers
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how portable is end iterator decrement?
Just encountered decrement of end() iterator in my company source codes and it looks strange for me. As far as I remember this was working on some platforms, but not for the others. Maybe I'm wrong, ...
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votes
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answers
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Portability of #warning preprocessor directive
I know that the #warning directive is not standard C/C++, but several compilers support it, including gcc/g++. But for those that don't support it, will they silently ignore it or will it result in a ...
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votes
9
answers
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Change the current working directory in C++
How can I change my current working directory in C++ in a platform-agnostic way?
I found the direct.h header file, which is Windows compatible, and the unistd.h, which is UNIX/POSIX compatible.
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votes
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Multi-character constant warnings
Why is this a warning? I think there are many cases when is more clear to use multi-char int constants instead of "no meaning" numbers or instead of defining const variables with same value. When ...
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votes
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answers
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Checking the gcc version in a Makefile?
I would like to use some gcc warning switchs that aren't available in older gcc versions (eg. -Wtype-limits).
Is there an easy way to check the gcc version and only add those extra options if a ...
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votes
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answers
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How do I detect if I'm running MATLAB or Octave?
I need to write code that should run equally well in Octave and on MATLAB. Problem is that it needs to do some GUI stuff, which MATLAB and Octave handle completely differently.
Is there a way I can ...
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votes
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answers
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views
Is there any guidance on converting existing .NET class libraries to portable libraries?
I have some class libraries with a non-trivial amount of existing code. The class libraries currently target .NET 4.0. Is there any guidance on how to convert these libraries to be portable libraries? ...
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votes
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When is the use of std::ref necessary? [duplicate]
Consider:
std::tuple<int , const A&> func (const A& a)
{
return std::make_tuple( 0 , std::ref(a) );
}
Is the std::ref required for writing correct and portable code? (It compiles ...
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votes
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answers
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Can placement new for arrays be used in a portable way?
Is it possible to actually make use of placement new in portable code when using it for arrays?
It appears that the pointer you get back from new[] is not always the same as the address you pass in (...
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votes
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answers
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views
What is the most portable/cross-platform way to represent a newline in go/golang?
Currently, to represent a newline in go programs, I use \n. For example:
package main
import "fmt"
func main() {
fmt.Printf("%d is %s \n", 'U', string(85))
}
... will yield 85 is U followed by ...
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votes
9
answers
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Portability of binary serialization of double/float type in C++
The C++ standard does not discuss the underlying layout of float and double types, only the range of values they should represent. (This is also true for signed types, is it two's compliment or ...
Matthieu N.
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votes
7
answers
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How to design a C / C++ library to be usable in many client languages? [closed]
I'm planning to code a library that should be usable by a large number of people in on a wide spectrum of platforms. What do I have to consider to design it right? To make this questions more specific,...
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votes
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answers
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Autotools vs CMake for both Windows and Linux compilation
I have been looking for pros & cons of Autotools and CMake. But I would like to know opinions from people having used one (or both) of these tools for projects.
I used Autotools very basically a ...
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votes
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answers
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msys path conversion (or cygpath for msys?)
I need to pass /DEF:c:\filepath\myLib.def" command line option from a bash script to MS compiler/linker. The path is generated as part of build process by a bash script. Basically, the argument that ...
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votes
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What's the difference between "int" and "int_fast16_t"?
As I understand it, the C specification says that type int is supposed to be the most efficient type on target platform that contains at least 16 bits.
Isn't that exactly what the C99 definition of ...
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C++: Is there a standard definition for end-of-line in a multi-line string constant?
If I have a multi-line string C++11 string constant such as
R"""line 1
line 2
line3"""
Is it defined what character(s) the line terminator/separator consist of?
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GLIBCXX versions
If I compile a C++ program on my machine, and run it on another one (with older software) I get: /usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.9' not found.
In fact on my system glibc is newer (I got ...
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votes
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answers
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What is the difference between a wrapper, a binding, and a port?
In a software portability context, what is the difference between these three concepts?
For example, I want to use the ncurses library, the original ncurses library is written in C, but my ...
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A step-up from TiddlyWiki that is still 100% portable?
TiddlyWiki is a great idea, brilliantly implemented. I'm using it as a portable personal "knowledge manager," and these are the prize virtues:
It travels on my USB flash memory stick and runs on any ...
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answers
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What is the smallest possible Windows (PE) executable?
As a precursor to writing a compiler I'm trying to understand the Windows (32-bit) Portable Executable format. In particular I'd like to see an example of a bare-bones executable which does nothing ...
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votes
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answers
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Building a 32-bit float out of its 4 composite bytes
I'm trying to build a 32-bit float out of its 4 composite bytes. Is there a better (or more portable) way to do this than with the following method?
#include <iostream>
typedef unsigned char ...
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How do you deal with Internet Explorer?
I am aware that there are probably other questions regarding this topic. I guess that every web developer goes through this with IE.
My problem:
I am developing a web-based application fully based on ...
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votes
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answers
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Correct, portable way to interpret buffer as a struct
The context of my problem is in network programming. Say I want to send messages over the network between two programs. For simplicity, let's say messages look like this, and byte-order is not a ...
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votes
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c++ Initializing a struct with an array as a member
Edited again because it originally wasn't clear that I'm trying to initialize the arrays at compile time, not at run time...
I've got the following reduced testcase:
typedef struct TestStruct
{
...
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How should I handle "cast from ‘void*’ to ‘int’ loses precision" when compiling 32-bit code on 64-bit machine?
I have a package that compiles and works fine on a 32-bit machine. I am now trying to get it to compile on a 64-bit machine and find the following error-
error: cast from ‘void*’ to ‘int’ loses ...
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votes
12
answers
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How to write portable code in c++?
What are the things that I should keep in mind to write portable code? Since I'm a c++ beginner, I want to practice it since beginning.
Thanks.
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