I get build error - undefined reference to 'stat64@GLIBC_2.33'

[pataxis]

When I try to build my ACAP application, I get an error undefined reference to 'stat64@GLIBC_2.33'.
How can I fix this?

[pataxis]

Errors like this complaining on an undefined reference to a function or symbol in GLIBC_2.XX is something we have seen during development and test of the ACAP SDK. It has occurred when there is a mismatch in libc versions.

ACAP SDK and libc version

The compatibility of an SDK is discussed in ACAP 3 SDK documentation and in ACAP 4 SDK documentation.

When you build an application with an SDK version according to our ACAP application examples, you will build and link the application with a certain libc version that is also found in the corresponding AXIS OS version. Any API libraries in the SDK that you link to in your application have been built with the same libc version.

Since libc is backwards compatible, it means that building the application with a libc version and linking to API libraries compiled with the same libc version, your application will be possible to install on the specified AXIS OS version or later.

Building an application with for example ACAP SDK 4.1 (glibc 2.33) will make it compatible with AXIS OS 10.9 or later.

The ACAP application build procedure is using make underneath and some things are assumed here to build with the correct libc version.

1. Source the build environment file /opt/axis/acapsdk/environment-setup* to set build environment variables like CC used in Makefile. The variables are set up to point to the SDK path which contains the correct libc version.

   RUN . /opt/axis/acapsdk/environment-setup* && \
   acap-build .

   If you have built ACAP applications before and it has only package.conf and no manifest.json, there is information in ACAP 3 documentation how to move to the new format.
2. In Makefile, if you are linking to API libraries in the SDK path, use pkg-config to expand dependencies. See for example the vdostream example.

   CFLAGS += $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --cflags $(PKGS))
   LDLIBS += $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --libs $(PKGS))

3. The build step in the Makefile use the environment variables with correct SDK paths

   $(CC) $(CFLAGS) $(LDFLAGS) $^ $(LDLIBS) -o $@

Wrong libc version and errors

We have seen errors similar to undefined reference to 'stat64@GLIBC_2.33' in tests and development. They have occurred when linking to an API library in the SDK which is compiled with a newer libc version like 2.33 but GCC is wrongly using the libc of the Ubuntu container image which is an older libc version like 2.31 and therefore can't find the newer 2.33 symbols/functions.

Not following the steps outlined above could lead to this. Here are some possible pitfalls:

• Not sourcing the SDK environment
• Not expanding the API dependencies with pkg-config
• Not using make and Makefile
• Building libraries with a newer libc version on a build machine and then copy them in to the ACAP SDK container image which has an older libc version. See the examples for utility-libraries for how libraries can be built inside the SDK environment instead.

Other build tools than make

Building the ACAP application with other tools than make and Makefile is not something that is supported today.

If you want or need to use other build tools, the above information can hopefully be of some help. Another thing could be to run the SDK environment interactively, check the content of the cross compilation variables by running env and try to translate them.