Questions tagged [nothrow]
25 questions
34
votes
9 answers
When should std::nothrow be used?
What is the ideal usage of std::nothrow?
blitzkriegz
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18
votes
2 answers
How to combine std::make_shared and new(std::nothrow)
C++'s new has an option to return a null pointer instead of throwing a bad_alloc exception when an allocation failed.
Foo * pf = new(std::nothrow) Foo(1, 2, 3);
(Yes, I understand this only prevents the new from throwing a bad_alloc; it doesn't…
Adrian McCarthy
- 45,555
- 16
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15
votes
1 answer
Do std::make_shared and std::make_unique have a "nothrow" version?
For the new operator, we have the std::nothrow version:
std::unique_ptr p = new(std::nothrow) T();
Do we have something like this for the std::make_shared or std::make_unique?
jack sparow
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- 9
7
votes
3 answers
Operator new with nothrow option still throws exception
There is such code:
#include
int main(){
for(;;){
int* ptr = new (std::nothrow) int;
if(ptr == 0){
std::cout << 0 << std::endl;
break;
}
}
std::cin.get();
return…
scdmb
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5
votes
2 answers
Why is std::pair not nothrow constructible?
The following code:
#include
#include
#include
#include
using namespace std;
struct Foo
{
std::string s;
int i;
};
int main()
{
cout << boolalpha << is_nothrow_constructible::value << endl;
…
Nick
- 10,309
- 21
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- 201
5
votes
4 answers
Placement new and exceptions
The "placement new" operator is declared as such:
void* operator new (std::size_t size, void* ptr) noexcept;
But while it doesn't involve any actual allocation so bad allocation exceptions are eliminated, it is still possible that the pointer…
user3735658
4
votes
3 answers
Is std::string's default constructor no-throw?
Can
std::string s;
throw under any circumstances? Is this regulated by the standard (interested in C++03, in case there are differences)?
Irfy
- 9,323
- 1
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3
votes
1 answer
Why `std:variant`'s `operator=(T&& t)`'s noexcept spec doesn't depend on inner types's destructor's noexcept spec?
Long title: Why std:variant's operator=(T&& t)'s noexcept specification doesn't depend on inner types's destructor's noexcept specification?
I can see on cppreference that
template variant& operator=(T&& t) noexcept(/* see below…
Mate059
- 103
- 5
3
votes
2 answers
C++ Memory allocation with operator new: What are the methods of detecting and processing allocation errors?
In previous programs I have used the following code to check for memory allocation failures, usually without thinking about alternatives:
int* p_int = new int[10];
if(!p_int)
{
// We failed, so exit
return EXIT_FAILURE;
}
This method is…
FreelanceConsultant
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3
votes
2 answers
How to fail a constructor with new(std::nothrow)?
Consider the following code:
#include
#include
#include
void * operator new(size_t size) {
void *res;
if (size == 1) {
res = NULL;
} else {
res = malloc(size);
}
fprintf(stderr,…
Goswin von Brederlow
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3
votes
2 answers
What is the use of std::nothrow and std::new_handler in standard header file
I came across a small standard header file . I have probably not seen its direct use before. Here is the g++ version for those who are interested.
Below part is of my interest:
struct nothrow_t { };
extern const nothrow_t nothrow;
/** If…
iammilind
- 68,093
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2
votes
1 answer
Does specifying a constructor as noexcept implicitly result in the nothrow version of the new operator being used in C++?
If I specify a constructor as noexcept, does the nothrow version of the new operator implicitly get used when the object is dynamically instantiated?
For example:
class Something {
public:
Something() noexcept;
};
...
Something *s = new…
Billy
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2
votes
1 answer
new(std::nothrow) int[n] throws an exception
#include
#include
int main()
{
int n = -1;
try
{
int *p = new(std::nothrow) int[n];
if(!p)
std::cout << "new expression returned nullptr\n";
}
catch(const std::bad_array_new_length&…
Lassie
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2
votes
1 answer
what to do upon failure of memory allocation new (nothrow) in c++ on linux
under no-exception context, I have seen several posts saying
Thing* t = new(std::nothrow) Thing; // returns NULL on failure
if (!t) {
// allocation failure
}
e.g.
How to check memory allocation failures with new operator?
How to find out the…
pepero
- 7,095
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2
votes
1 answer
How to specify nothrow exception specifier for destructor?
I am trying to specify that a function is nothrow whenever the destructor of Foo doesn't throw. I can do this by using the type trait std::is_nothrow_destructible<>. How can I do this directly? I've tried the following, but it doesn't compile if I…
vsoftco
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