C library (libc) interfaces

The C library (libc) contains the system calls described in the Section 2 manual pages, and the function calls described in the Section 3C manual pages and Section 3S manual pages.

This ``API compatibility'' topic is concerned with libc function calls; for compatibility information for system calls defined in libc (and compatibility for other basic system services), see ``Base kernel compatibility''.

C library compatibility with earlier releases is provided through these libraries on UnixWare 7:

/usr/ccs/lib/libc.so

The UnixWare 7 compile-time libc. This is the version used (by default) by the UnixWare 7 link editor when you compile a program on &gemini. It defines the UnixWare 7 libc API, and provides source compatibility for SCO UnixWare 2.1.X-developed source code.

/usr/lib/libc.so.1

The UnixWare 7 run-time libc. This is the version of libc loaded by the dynamic linker by default into every process on the system. It defines the UnixWare 7 libc API, and provides binary compatibility for SCO UnixWare 2.1.X-developed executables.

/OpenServer/lib/libc.so.1

The UnixWare 7 run-time libc. For SCO OpenServer-compiled applications only. This is the version of libc loaded by the dynamic linker into every process on the system that is running a binary marked as an SCO OpenServer binary.

Binary and source compatibility for SCO UnixWare 2.1.X executables and source code is provided in the run-time and compile-time libc implementations, respectively. All SCO UnixWare 2.1.X-compiled binaries that conform to the documented SCO UnixWare 1 and 2 libc interfaces will load and run as expected on UnixWare 7. Similarly, all SCO UnixWare 2.1.X libc source will compile and run successfully on UnixWare 7.

Binary compatibility for SCO OpenServer-compiled binaries is provided through the /OpenServer/lib/libc.so.1 version of libc, which is loaded by the dynamic linker for any executable that is appropriately marked as an SCO OpenServer binary (see elfmark(1)).

Source code compatibility issues for SCO OpenServer applications are described in ``Source code compatibility for SCO OpenServer applications''.

The functions that are available to programmer's using the UnixWare and OpenServer Development Kit to compile application for either (or both) SCO OpenServer or SCO UnixWare 2.1.X are described in ``Binary compatibility for SCO OpenServer'' and ``Binary compatibility for SCO UnixWare 2.1.X''.