POSIX-conforming application support enhances code portability
The IEEE Portable Operating System Interface (POSIX) standard is a series of industry standards for code and user interface portability. POSIX support allows applications written for a UNIX-like operating system to be run on z/OS. C language programmers can access operating system services through a set of standard language bindings. C language programmers who install z/OS UNIX System Services (z/OS UNIX) and z/OS Language Environment can call C language functions defined in the POSIX standard from their C applications and can run applications that conform to ISO/IEC 9945-1:1990. 1 C language programmers with z/OS UNIX installed can also call a subset of the proposed programming interface for thread management (a subset of draft 6 of POSIX.4a). Through C interfaces, Language Environment® functions conform to XPG4.2 specifications and are branded by X/Open.
Applications that call POSIX functions can perform limited ILC under Language Environment (see z/OS Language Environment Writing Interlanguage Communication Applications for details). In addition, C POSIX-conforming applications may use all Language Environment services.
For an overview of z/OS UNIX, see z/OS Introduction and Release Guide.