15.6 Building Libraries for Public Use

When an organization builds a library for use by other organizations, the management of the libraries, platform generality, and other issues become significant. A simple test for whether or not a library is public is to ask if the application programmer can recompile the library easily. Public libraries should be built in conformance with the system’s application binary interface (ABI). In general, this means that any processor-specific options should be avoided. (For example, do not use– fast or– xtarget.)

The SPARC ABI reserves some registers exclusively for applications. For V7 and V8, these registers are %g2, %g3, and %g4. For V9, these registers are %g2 and %g3. Since most compilations are for applications, the C++ compiler, by default, uses these registers for scratch registers, improving program performance. However, use of these registers in a public library is generally not compliant with the SPARC ABI. When building a library for public use, compile all objects with the -xregs=no%appl option to ensure that the application registers are not used.