Initialization and Termination Functions

After the runtime linker has built the process image and performed the relocations, each shared object gets the opportunity to execute some initialization code.

Similarly, shared objects can have termination functions, which are executed with the atexit(3C) mechanism after the base process begins its termination sequence. Refer to atexit(3C) for more information.

Shared objects designate their initialization and termination functions through the DT_INIT and DT_FINI entries in the dynamic structure, described in "Dynamic Section" above. Typically, the code for these functions resides in the .init and .fini sections, mentioned in "Sections" earlier.

Although the atexit(3C) termination processing normally will be done, it is not guaranteed to have executed upon process death. In particular, the process will not execute the termination processing if it calls _exit() or if the process dies because it received a signal that it neither caught nor ignored.