PH62468: NEW FUNCTION - Additional Support for C/C++ Thread Local Storage

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• NEW FUNCTION
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of C/C++ Thread Local Storage (TLS)    *
  ****************************************************************
  * PROBLEM DESCRIPTION: A C or C++ program that uses thread     *
  *                      local storage and initializes a thread  *
  *                      local variable to the address of global *
  *                      variable cannot be built successfully.  *
  *                      The compile with the Open XL C/C++ 2.1  *
  *                      compiler will be successful, but the    *
  *                      bind will fail with error message       *
  *                      IEW2353E.                               *
  ****************************************************************
  See problem description.
  

Problem conclusion

Temporary fix

Comments

• Additional Support for C/C++ Thread Local Storage (TLS).
  - Allow initialization of a thread local storage variable to
    the address of a global (WSA) variable
  
  The following publication must be updated.
  ================================================================
  z/OS Language Environment Vendor Interfaces (SA38-0688)
  In part Language Environment vendor interfaces for AMODE 64
  applications
  In chapter Storage management for AMODE 64 applications
  In section __tls_get_addr() - Compiler-writer interface in
  support of thread-local variables
  Replace the Syntax section with the following:
  #include <__le_cwi.h>
  
  void __tls_get_addr(tls_index_t *ti);
  
  typedef struct
  {
    unsigned long int   *ti_module;
    unsigned long int    ti_offset;
  }tls_index_t;
  
  Replace the description of the parameters with the following:
  ti(input)
  The address of a tls_index_t which contains the identity
  information of one thread local storage (TLS) variable.
  The tls_index_t has two fields which are used differently
  depending on which method is used to allocate the TLS template:
  
    ti_module
    The 8-byte address of an 8-byte field which identifies a
    module.
    New method:
      The address of field @@TLS@MOD@ID in class C_WSA64.
    Old method:
      The address of field @@TLS@MODULEID in class C_WSA64.
  
    ti_offset
    An 8-byte offset for the TLS variable from the beginning
    of the TLS template.
    New method:
      The offset from variable @@TLS@BEGIN in class C_WSA64.
    Old method:
      The offset from the beginning of class C_TLS64.
  
  Add the following Usage Note:
  When a module that uses thread local storage (TLS) is loaded,
  a TLS template (an image of what the TLS looks like) is
  allocated. This TLS template is copied when TLS is allocated
  for a thread.
  
  There are two methods which are used to create a TLS template.
  
  The new and preferred method:
  - A TLS variable can be initialized to the address of
    a writable static variable using this method.
  - Define fields for TLS variables in the class C_WSA64
    with priority greater than 101 and less than 199 (e.g. 150).
  - For the module id field, use the field @@TLS@MOD@ID in
    class C_WSA64.
  - For offset for the TLS variable from the beginning of the
    TLS template, use the calculation -- offset of the field
    for the TLS variable in class C_WSA64 minus the offset of
    the field @@TLS@BEGIN in class C_WSA64.
  - During binder AUTOCALL processing member CELQTLSI in
    data set SCEEBND2 will get included to resolve the
    references to @@TLS@MOD@ID and @@TLS@BEGIN.
  
  The old method:
  - A TLS variable cannot be initialized to the address of
    a writable static variable using this method.
  - Define fields for TLS variables in the class C_TLS64.
  - For the module id field, use the field @@TLS@MODULEID
    in class C_WSA64.
  - For offset for the TLS variable from the beginning of the
    TLS template, use offset of the field for the TLS variable
    in class C_TLS64.
  - During binder AUTOCALL processing member CELQTLSO in
    data set SCEEBND2 will get included to resolve the
    references to @@TLS@MODULEID.
  
  
  z/OS Language Environment Runtime Messages (SA38-0686)
  Add two new abend reason codes to abend U4093 (X'FFD')
  
  X'23C' (572)
  The program object contains both class C_TLSINFO and class
  C_TLSINFO2. For programs that use thread local storage (TLS),
  each of these two classes is used for a different method of
  allocating the TLS template. Language Environment only supports
  using a single method in a program object.
  
  Most likely, the program object was created from more than one
  source part. Some parts were compiled using the older method
  and others were compiled using the newer method. To correct
  this problem, make sure that all parts that use thread local
  storage have been compiled using the same method. To see what
  method is used by the Open XL C/C++ compiler, please refer to
  IBM Open XL C/C++ for z/OS documentation.
  
  X'240' (576)
  Size of class C_TLSINFO is not 8 or size of class C_TLSINFO2
  is not 24.
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UO04849 UO04851

Modules/Macros

• CEEPPOS  CELHZDMD CELHZNMD CELQDIR7 CELQDIR9 CELQINC  CELQPOS
  CELQTLSI CELQTLSO CELQZDMD CELQZNMD EDC4022B EDC403B1
  

Fix information

• Fixed component name

  LE C LIB FOR Z/

• Fixed component ID

  568819805

Applicable component levels

• R7E0 PSY UO04851

     UP25/09/24 P F509  

• R7F0 PSY UO04849

     UP25/09/24 P F509  

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.