Writing and compiling threaded programs

When writing and compiling code that use threads or that run in a threaded job, make sure to do the following:

• Ensure that all of the APIs or system services that you use are threadsafe. See Multithreaded applications for an introduction to threads and general information about i5/OS threads.
  
  
• Insert the following lines into any module that uses the thread data types or definitions.

  #define _MULTI_THREADED
  

  #include <pthread.h>
  

  The preprocessor definition _MULTI_THREADED must come before the pthread.h.

  See Header files for Pthread functions for more information on header files.

  See Using the _MULTI_THREADED preprocessor definition for more information on the _MULTI_THREADED preprocessor definition.

• Compile the program normally; use the CRTCMOD followed by the CRTPGM or CRTSRVPGM commands. You can also use the CRTBNDC CL command to create your threaded program.
  
  
• Since Pthread APIs can operate on functions and data which could exist in different compilation units (modules), the same storage model and data model must be used throughout all compilation units within a program or service program that uses Pthread APIs. Otherwise, unpredictable behavior and failures will occur. Refer to the information on teraspace and single-level store in the ILE Concepts book for more information on storage model and data model.