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C and C++ library changes between RVCT v4.0 and ARM Compiler v4.1

Various changes have been made to the ARM C and C++ library in ARM Compiler toolchain v4.1.

The libraries now use more 32-bit encoded Thumb code on targets that support Thumb-2 technology. This is expected to result in reduced code size without affecting performance. The linker option --no_thumb2_library falls back to the old-style libraries if necessary.

Math function returns in some corner cases now conform to POSIX/C99 requirements. You can enable older behavior with:

#pragma import __use_rvct_matherr

From RVCT v4.0 09Q4 patch onwards, you can enable the newer behavior with:

#pragma import __use_c99_matherr.