IJ13545: MISSING __ATOMIC* EXTERNAL SYMBOLS

XL C/C++ for AIX, V16.1.0.2 Fix Pack (March 2019)

APAR status

• Closed as program error.

Error description

• When using C11 or C++11 atomic operations on struct/aggregate
  types, external function calls are made to a variety of
  __atomic* symbols.  During linking, these symbols are not found,
  so missing symbol errors occur.
  
  Atomic operations using primitive types of size 1/2/4/8 have
  inline code generated, and are not affected by this issue.
  

Local fix

Problem summary

• PROBLEM DESCRIPTION:
  The compiler generates calls to __atomic_*() routines for
  atomic operations because it does not generate inline
  instructions.  The XLC compiler has not been providing a
  library containing these routines.  This results in missing
  symbols at link time.
  
  USERS AFFECTED:
  Users who use C11 or C++11 atomic operations on types that the
  compiler does not generate inline instructions for.
  

Problem conclusion

• A port of the libatomic.a atomics library is being made
  available via this APAR to support cases where the compiler
  does not generate inline instructions for atomic operations.
  

Temporary fix

Comments

APAR Information

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

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

  IJ14873

Fix information

• Fixed component name

  XL C/C++ FOR AI

• Fixed component ID

  5725C7200

Applicable component levels

• RG10 PSY

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