Rebuilding a C++ application on Linux

C++ IBM MQ MQI client and server applications on Linux must be recompiled using GNU Compiler Collection (GCC) 4.1.2, or later. Compilers older than GCC 4.1.2 are no longer supported. The C++ GCC 4.1.2 run time libraries, or later, must be installed in /usr/lib or /usr/lib64

If you are using one of the supported Linux distributions, the libraries are correctly installed; see System Requirements for IBM MQ.

The GCC 4.1.2 libraries support SSL and TLS connections from an IBM MQ MQI client. SSL and TLS use GSKit version 8, which depends on libstdc++.so.6. libstdc++.so.6 is included in GCC 4.1.2.

Before you begin

Check the required level of GCC for your distribution of Linux; see System Requirements for IBM MQ.
If you are using SSL or TLS, also check the required level of libstdc++.so.
Check whether the application requires rebuilding. Run the following command to display what version of libstdc++.so the application depends upon. If the result is less than libstdc++.so.6, you must rebuild our application.
```
ldd ApplicationPath
```

About this task

The task describes the steps required to rebuild a Linux C++ IBM MQ application. For more detailed instructions about building Linux applications for IBM MQ ; see Building your procedural application on Linux

Procedure

Check that the required GCC library is installed correctly.
Run one of the following commands:
- Check the 32 bit library on an x86 Linux system:
```
ls -l /usr/lib/libstdc++.so.6
```
- Check the 64 bit library on any other Linux system.
```
ls -l /usr/lib64/libstdc++.so.6
```
Check that the GCC compiler is at least at version 4.1.2
Run the following command to display the version of GCC.
```
gcc -v
```
Rebuild the application
The commands to compile and link Linux C++ applications are described in Building 32-bit applications and Building 64-bit applications

What to do next

When you deploy your Linux C++ application, ensure that the same GCC runtime library is correctly installed on the run time system.