Libpqxx newest version download

There may be a bug in the library's throw specifications. When using gcc or a compatible compiler, you may be able to detect this by recompiling both the library and your own code with the -fno-enforce-eh-specs option. If the problem disappears when you do that, don't sit on it — report it! Sometimes connections to the database are lost even after they have been successfully established.

This can happen for many reasons: a broken cable, a power outage in the wrong place, a crashed server, a change to your network configuration, or even a firewall dropping your connection because it hasn't been used for too long.

Your program's default response to receiving this error is to abort. That can be useful for simple, short-lived programs but many more complex applications can not afford to crash just because they lose a network connection.

All you need to do deal with broken connections in libpqxx on Unix-like systems and that includes GNU and BSD systems as well as macOS is to make your program ignore this signal.

Just include something like this in your program:. Your code can then handle that like it can any other exception. From here you can search these documents. Enter your search terms below. Home Faq Search Previous Next. Frequently Asked Questions General questions Is libpqxx really "official"?

Why not? I hope you like the result. Can I become a project member? What platforms does libpqxx run on? What PostgreSQL versions are supported? Isn't "Postgre" a strange name? That's why it's not actually the name. The correct short version of PostgreSQL is postgres, with the "s" at the end. Feature Questions Data is transferred in text form. Can I make it work directly in binary? There are good reasons for this: The binary format may change between postgres versions.

No guarantees. Binary representations are undcoumented. We have no good way to check that the server actually speaks the exact format we expect. Nevertheless, there are special cases where binary transfers do make sense, and libpqxx does support these: Large objects, a. Can I let libpqxx write data from the database directly into my objects? Streaming queries will let you map fields directly into local variables, but not into the members of an object: for auto [id, name]: tx.

Can you expose this C-level libpq structure that libpqxx hides from me? Can I have two or more simultaneous transactions? If you want to have multiple concurrent transactions, let them work on different connections. Questions about Building libpqxx and your own code Will it work with my compiler? Can I build libpqxx and my own application with different compilers? Do I need libpq when I use libpqxx?

Usually this means one or more of: You need to link to libpq as well as to libpqxx. You need to link to libpqxx first, and then to libpq. If you have them, don't link "Release" artefacts with "Debug" ones. How compatible are different libpqxx versions? Releases are versioned like x. Can I build a dynamic library? Are shared libraries a good idea? The answer depends on your OS. Why can't the build procedure find libpq? It's in plain sight! The build has several different ways of finding the libpq library and headers: CMake The CMake build uses the standard CMake machine for finding the PostgreSQL package, but there are ways of overriding it if that doesn't work.

When building in the Release flavour, use only the Release-flavoured libraries. The libpqxx headers try to work around this silly problem, but it's easy to forget. Troubleshooting Questions I'm running into a bug. What can I do? Does WinZip mess up the source tree? I can't catch exceptions! Why does my program crash when a connection to the database breaks? Why does my program crash when it fails to connect to the database? Instructions for building from source can be found in the documentation.

There are source code and binary packages of beta and release candidates, and of the current development code available for testing and evaluation of new features. Note that these builds should be used for testing purposes only , and not for production systems. Can't have a database example without an Employee table. Here's a simple application: find an employee by name, and raise their salary by 1 whatever-it-is-they-get-paid-in.

This example is so simple that anything that goes wrong crashes the program. You won't need to do a lot more to fix that, but we'll get to it later. You'll find more detailed explanations and reference-style docs on the ReadTheDocs site. Remember to keep the -lpqxx and -lpq in that order! Otherwise the linker will complain bitterly about missing functions like PQconnectdb and PQexec.

It works differently on Microsoft Windows, though there are development environments out there that behave more like a Unix system. Errors are exceptions, and derived from std::exception , just like you'd expect. So you can handle database errors like all others:. Of course libpqxx also defines its own exception hierarchy for errors it throws, so you can handle those specially if you like:. Just one caveat: not all platforms support throwing an exception in a shared library and catching it outside that shared library.

Unless you're building for Windows, it's probably a good habit to use static libraries instead. The contents are immutable. From here you can search these documents. Enter your search terms below. Home Faq Search Previous Next. Code, bug tracker, and releases are on Github. Stats and insights are in OpenHub News Obscure but dangerous encoding issue uncovered. How big is your risk of data corruption?

It all depends: If your application never changes the client encoding, my understanding is that you'll have no problem — the server and client encodings will be identical, and so there will be no room for misunderstanding between them. We saved up so many changes, I couldn't wait any longer.

Mark zview as a view and as a borrowed range. More generic escaping functions, supporting more types of binary. Quick example Can't have a database example without an Employee table. Building your libpqxx program The details depend on your system and compiler. Handling errors Errors are exceptions, and derived from std::exception , just like you'd expect.

Complete example Here's a more complete example, showing iteration and direct field access. Return result.