473,909 Members | 4,189 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

hash_map question

On http://www.sgi.com/tech/stl/hash_map.html it says that hash_map is
only an extension of the SGI implementation, not a part of the C++
standard. But in g++ 4.1.3 I can manage it to work using the header
<ext/hash_mapand the namespace __gnu_cxx. So, it is present in more
implementations , not just SGI. Is this a thing I can trust in? Will I
always find hash_map on all new g++ versions? Should I care about
portability or it is safe to use it?
Feb 16 '08 #1
1 1664
Stefan Istrate wrote:
On http://www.sgi.com/tech/stl/hash_map.html it says that hash_map is
only an extension of the SGI implementation, not a part of the C++
standard. But in g++ 4.1.3 I can manage it to work using the header
<ext/hash_mapand the namespace __gnu_cxx. So, it is present in more
implementations , not just SGI. Is this a thing I can trust in? Will I
always find hash_map on all new g++ versions? Should I care about
portability or it is safe to use it?
Not if you want maximum portability. hash_map will be in the next
revision of the standard.

--
Ian Collins.
Feb 16 '08 #2

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

4
5855
by: Christian Meier | last post by:
Hello, Yes, I know that hash maps aren't in the standard. But I couldn't find any better newsgroup for this post. (or is there an SGI library newsgroup?) I am currently testing the hash_map implementation of SGI. And now I am not sure if it is really true, what I discovered.... Here is my code:
5
8634
by: peter_k | last post by:
Hi I've defined hash_map in my code using this: ------------------------------------------- #include <string> #include <hash_map.h> & namespace __gnu_cxx {
1
2979
by: anjangoswami06 | last post by:
Hi, I am interested to know how it is possible to update the data type with "insert" with stl hash_map. Suppose we have, hash_map<const char *, MyDataType, hash_compare<const char*, some_compare_func_obj>> x; //I want to insert a new instance of MyDataType if a new key is encountered but if it is a key //which already exists I want to update
4
3221
by: newbie | last post by:
For STL containers like hash_map, need I explicitly call clear() before delete()ing it? e.g. hash_map<string, MyClass**my_map; my_map = new (hash_map<string, MyClass*>); .... ....
11
1228
by: aaragon | last post by:
Hello everyone, I have a VERY BIG set of double values that I want to map to intervals so I thought a clever way to do this was using a hash table. Let's say that I want to map all double values in the range 0-0.5 to a single std::pair<double,double>. This is what I've done so far: #include <iostream>
1
1777
by: Axel Gallus | last post by:
Hello, i have a question concerning STL non-standard hash_maps under Visual Studio 2005: Microsoft STL requires a "hash_compare" object for hash_maps: template <class Key, class Type, class Traits=hash_compare<Key, less<Key, class Allocator=allocator<pair <const Key, Type > class hash_map
2
4290
by: Amit Bhatia | last post by:
Hi, I am trying to use hash maps from STL on gcc 3.3 as follows: #ifndef NODE_H #define NODE_H #include <ext/hash_map> #include "node_hasher.h" class Node; typedef hash_map<pair<int,int>, Node, Node_HasherLoc_Tree;
5
3382
by: frankw | last post by:
Hi, I have a hash_map with string as key and an object pointer as value. the object is like class{ public: float a; float b; ...
2
8169
by: marek.vondrak | last post by:
Hi, I am wondering if there are any functional differences between SGI's hash_map and tr1's unordered_map. Can these two containers be interchanged? What would it take to switch from hash_map to unordered_map? Thank you. -Marek
0
10035
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
11346
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
1
11046
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9725
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
7248
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5938
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
6138
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4774
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
4336
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.