Thread management

POSIX-conforming C/C++ applications can communicate with Enterprise COBOL for z/OS programs compiled THREAD on any thread.

POSIX-conforming C/C++ applications can communicate with the following COBOL programs on only one thread:

Enterprise COBOL for z/OS (compiled NOTHREAD)
COBOL for OS/390 & VM
COBOL for MVS & VM
COBOL/370
VS COBOL II

POSIX-conforming C/370™ applications can communicate with assembler routines on any thread when the assembler routines use the CEEENTRY/CEETERM macros or the EDCPRLG/EDCEPIL macros provided by C/C++.

OS/390-conforming C applications can communicate with PL/I on any thread created by C routines. PL/I routines, however, must follow the rules described in z/OS Language Environment Programming Guide.

If an asynchronous signal is being delivered to a thread, the thread is interrupted for the signal only when the execution is:

In a user C routine,
Just prior to a return to a C routine
In an Enterprise COBOL for z/OS program compiled with the THREAD option
Just prior to return to Enterprise COBOL for z/OS program compiled with the THREAD option, or
Just prior to an invocation of a Language Environment library from a user routine

C routines or COBOL routines compiled with the THREAD compiler option may need to protect against asynchronous signals based on the application logic including the possible use of the POSIX signal-blocking function that is available. For all other routines, it does not have to be concerned about being interrupted during its execution for an asynchronous signal.