IBM XL Compilers with AIX 5L: Compiler Flags, Environment Settings and Utilities

Optimization Flags

• • -bmaxdata:0x20000000, -bmaxdata:0x40000000, -bmaxdata:0x50000000, -bmaxdata:0x60000000, -bmaxdata:0x80000000
  • -bmaxdata:(\S+)\b

  • Causes the system loader to put the heap in it's own segment of the size specified. This is only required for 32-bit applications, as their segments are 256M. If the last digit of the value is "C", then it also turns off the malloc pool option for that executable.

• • -bdatapsize:64K
  • -bdatapsize:64K\b

  • Specifies a non-default page size of 64K for the program data segment.

• • -bstackpsize:64K
  • -bstackpsize:64K\b

  • Specifies a non-default page size of 64K for the program stack segment.

• • -btextpsize:64K
  • -btextpsize:64K\b

  • Specifies a non-default page size of 64K for the program text segment.

• • -blpdata
  • -blpdata\b

  • Sets the bit in the file's XCOFF header indicating that this executable will request the use of large pages when they are available on the system and when the user has an appropriate privilege

• • -D__IBM_FAST_VECTOR
  • -D__IBM_FAST_VECTOR\b

  • The __IBM_FAST_VECTOR macro defines a different iterator for the std::vector template class. This iterator results in faster code, but is not compatible with code using the default iterator for a std::vector template class. All uses of std::vector for a data type must use the same iterator. Add -D__IBM_FAST_VECTOR to the compile line, or "#define __IBM_FAST_VECTOR 1" to your source code to use the faster iterator for std::vector template class. You must compile all sources with this macro.

• • -D_ILS_MACROS
  • -D_ILS_MACROS\b

  • Causes AIX to define "ischar()" (and friends) as macro's and not subroutines.