IV16478: ISSUES WITH BOOL VAL AND CC

March 2012 PTF for XL C Enterprise Edition for AIX, V9.0
March 2012 PTF for XL C/C++ Enterprise Edition for AIX, V9.0

APAR status

• Closed as program error.

Error description

• When compiling with the cc compiler, the resulting exe produces
  an incorrect output.
  
  
  ===== COMPILE COMMAND:
  cc test.c
  
  ===== TESTCASE:
  $cat test.c
  #include <stdio.h>
  #include <stdbool.h>
  
  #ifdef THIS_WORKS
  #  define cBOOL(cbool) ((cbool) ? true : false)
  #else
  #  define cBOOL(cbool) ((bool)!!(cbool))
  #endif
  
  #define toUPPER(c) (cBOOL((c >= 'a' && c <= 'z')) ? (c - 32) :
  (c))
  
  int
  main(int argc, char **argv) {
      while (*++argv) {
          char c = **argv;
          char u = toUPPER(c);
          printf("c=%d u=%d\n", c, u);
      }
      return 0;
  }
  $
  
  
  ===== ACTUAL OUTPUT:
  $cc test.c
  $./a.out
  $ ./a.out v V
  c=118 u=86
  c=86 u=54
  $
  
  
  ===== EXPECTED OUTPUT:
  $cc test.c
  $./a.out v V
  c=118 u=86
  c=86 u=86
  $
  

Local fix

• It will produce the expected output if you compiled the
  test case as a C++ program.
  

Problem summary

• USERS AFFECTED:
  Users who cast a non-constant expression to _Bool may be
  affected by this issue.
  
  PROBLEM DESCRIPTION:
  Casting a non-constant expression to _Bool returns incorrect
  results.
  

Problem conclusion

• When the expression being casted to _Bool is non-contant, the
  compiler should not just pick 0 or 1 but propagate the
  non-contant value.
  This has been corrected.
  

Temporary fix

Comments

APAR Information

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

  IV11885

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

Fix information

• Fixed component name

  XL C AIX

• Fixed component ID

  5724S7000

Applicable component levels

• R900 PSN U850264

     UP06/09/13 C