Look my code seems to be correct, according to all the documentation I can find online. My IDE is MS Visual Studio Xpress 4 Windows Desktop 2012, and it's compiler is throwing up the error:
Error 1 error C3861: 'setenv': identifier not found e:\users\owner\documents\visual studio 2012\projects\project1\project1\source1.cpp 18 1 Project1.
Help me!!!
#include <windows.h>
#include <sstream>
#include <ostream>
#include <cstdlib>
#include <iostream>
#include <stdlib.h>
using namespace std;
int howManyInClass = 0;
int main(){
long checklength = sizeof(getenv("classSize"))/sizeof(*getenv("classSize"));
if (checklength==0){
cout<<"Please enter the ammount of students in your class";
cin>> howManyInClass;
cin.ignore();
setenv("classSize", howManyInClass, 1);}
};
Microsoft's runtime library doesn't support the standard setenv() function. You could use their replacement _putenv() or, for portable code, I prefer to use a simple wrapper.
Here's my wrapper with the standard interface:
int setenv(const char *name, const char *value, int overwrite)
{
int errcode = 0;
if(!overwrite) {
size_t envsize = 0;
errcode = getenv_s(&envsize, NULL, 0, name);
if(errcode || envsize) return errcode;
}
return _putenv_s(name, value);
}
You can either use _putenv() which takes a string parameter as the string classSize=7;
ostringstream classSize;
classSize << "classSize=" << howManyInClass;
_putenv(classSize.str().c_str());
...or (preferably) the security enhanced _putenv_s() that takes the key and the value as separate (const char*) parameters;
ostringstream classSize;
classSize << howManyInClass;
_putenv_s("classSize", classSize.str().c_str());
Try _putenv instead of setenv.
msdn _putenv
the reason you encountered the linkage error is that, if you take a look at the content of the library of stdlib.h, you will find that, setenv() is not declared there. At the first glance, it is a C standard API, but looks like Windows do not follow all of the standard. Or, you might be able to configure your VS to use CRT instead of Windows runtime, in that case, I think setenv will be identified.
Related
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}
Below is a snippet to show the basic structure of my code right now. On that last line, Visual Studio is saying "no instance of overloaded function that matches the argument list". According to the references I can find from VS help, however, this is exactly how the function should be used. I have string and iostream included, and I have precompiled headers turned off, so I'm not sure if the fault for VS not recognizing this function is on me or not.
#include <iostream>
#include <vector>
#include <string>
int main(){
Stack<double> nums;
std::string input;
std::string::size_type index;
std::cin >> input;
double num = std::stod(input, index);
}
It should be a pointer to size_type. Verified in VS.
double num = std::stod(input, &index);
When overloading is around, you must be precise :)
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}
Look my code seems to be correct, according to all the documentation I can find online. My IDE is MS Visual Studio Xpress 4 Windows Desktop 2012, and it's compiler is throwing up the error:
Error 1 error C3861: 'setenv': identifier not found e:\users\owner\documents\visual studio 2012\projects\project1\project1\source1.cpp 18 1 Project1.
Help me!!!
#include <windows.h>
#include <sstream>
#include <ostream>
#include <cstdlib>
#include <iostream>
#include <stdlib.h>
using namespace std;
int howManyInClass = 0;
int main(){
long checklength = sizeof(getenv("classSize"))/sizeof(*getenv("classSize"));
if (checklength==0){
cout<<"Please enter the ammount of students in your class";
cin>> howManyInClass;
cin.ignore();
setenv("classSize", howManyInClass, 1);}
};
Microsoft's runtime library doesn't support the standard setenv() function. You could use their replacement _putenv() or, for portable code, I prefer to use a simple wrapper.
Here's my wrapper with the standard interface:
int setenv(const char *name, const char *value, int overwrite)
{
int errcode = 0;
if(!overwrite) {
size_t envsize = 0;
errcode = getenv_s(&envsize, NULL, 0, name);
if(errcode || envsize) return errcode;
}
return _putenv_s(name, value);
}
You can either use _putenv() which takes a string parameter as the string classSize=7;
ostringstream classSize;
classSize << "classSize=" << howManyInClass;
_putenv(classSize.str().c_str());
...or (preferably) the security enhanced _putenv_s() that takes the key and the value as separate (const char*) parameters;
ostringstream classSize;
classSize << howManyInClass;
_putenv_s("classSize", classSize.str().c_str());
Try _putenv instead of setenv.
msdn _putenv
the reason you encountered the linkage error is that, if you take a look at the content of the library of stdlib.h, you will find that, setenv() is not declared there. At the first glance, it is a C standard API, but looks like Windows do not follow all of the standard. Or, you might be able to configure your VS to use CRT instead of Windows runtime, in that case, I think setenv will be identified.
so I have this code:
#include "stdafx.h"
#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;
...
char* b = new char [10];
strcpy(b, "1234567890");
error: microsoft visual studio 11.0\vc\include\string.h(110) : see declaration of 'strcpy'
How do I fix it?
A quick fix is to add the _CRT_SECURE_NO_WARNINGS definition to your project's settings
Right-click your C++ and chose the "Properties" item to get to the properties window.
Now follow and expand to, "Configuration Properties"->"C/C++"->"Preprocessor"->"Preprocessor definitions".
In the "Preprocessor definitions" add
_CRT_SECURE_NO_WARNINGS
but it would be a good idea to add
_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)
as to inherit predefined definitions
IMHO & for the most part this is a good approach.
There's an explanation and solution for this on MSDN:
The function strcpy is considered unsafe due to the fact that there is
no bounds checking and can lead to buffer overflow.
Consequently, as it suggests in the error description, you can use
strcpy_s instead of strcpy:
strcpy_s( char *strDestination, size_t numberOfElements,
const char *strSource );
and:
To disable deprecation, use
_CRT_SECURE_NO_WARNINGS. See online help for details.
http://social.msdn.microsoft.com/Forums/da-DK/vcgeneral/thread/c7489eef-b391-4faa-bf77-b824e9e8f7d2
The message you are getting is advice from MS that they recommend that you do not use the standard strcpy function. Their motivation in this is that it is easy to misuse in bad ways (and the compiler generally can't detect and warn you about such misuse). In your post, you are doing exactly that. You can get rid of the message by telling the compiler to not give you that advice. The serious error in your code would remain, however.
You are creating a buffer with room for 10 chars. You are then stuffing 11 chars into it. (Remember the terminating '\0'?) You have taken a box with exactly enough room for 10 eggs and tried to jam 11 eggs into it. What does that get you? Not doing this is your responsibility and the compiler will generally not detect such things.
You have tagged this C++ and included string. I do not know your motivation for using strcpy, but if you use std::string instead of C style strings, you will get boxes that expand to accommodate what you stuff in them.
I had to use strcpy_s and it worked.
#include "stdafx.h"
#include<iostream>
#include<string>
using namespace std;
struct student
{
char name[30];
int age;
};
int main()
{
struct student s1;
char myname[30] = "John";
strcpy_s (s1.name, strlen(myname) + 1 ,myname );
s1.age = 21;
cout << " Name: " << s1.name << " age: " << s1.age << endl;
return 0;
}
Add this line top of the header
#pragma warning(disable : 4996)
If you are getting an error saying something about deprecated functions, try doing #define _CRT_SECURE_NO_WARNINGS or #define _CRT_SECURE_NO_DEPRECATE. These should fix it. You can also use Microsoft's "secure" functions, if you want.
For my problem, I removed the #include <glui.h> statement and it ran without a problem.