The __user_libspace static data area holds
the static data for the C libraries. This is a block of 96 bytes
of zero-initialized data, supplied by the C library. It is also
used as a temporary stack during C library initialization.
The default ARM C libraries use the __user_libspace area
to hold:
errno, used by any function that is capable of settingerrno. By default,__rt_errno_addr()returns a pointer toerrno.The Floating-Point (FP) status word for software floating-point (exception flags, rounding mode). It is unused in hardware floating-point. By default,
__rt_fp_status_addr()returns a pointer to the FP status word.A pointer to the base of the heap (that is, the
__Heap_Descriptor), used by all themalloc-related functions.The current locale settings, used by functions such as
setlocale(), but also used by all other library functions that depend on them. For example, thectype.hfunctions have to access theLC_CTYPEsetting.
The C++ libraries use the __user_libspace area
to hold:
the
new_handlerfield andddtor_pointer:the
new_handlerfield is used to keep track of the value passed tostd::set_new_handler()the
ddtor_pointer, that points to a list of destructions to be performed on program exit. For example, objects constructed outside function scope exist for the duration of the program, but require destruction on program exit. Theddtor_pointeris used by__cxa_atexit()and__aeabi_atexit().
C++ exception handling information for functions such as
std::set_terminate()andstd::set_unexpected().
Note
How the C and C++ libraries use the __user_libspace area
might change in future releases.
See also- Other information
__aeabi_atexit()in C++ ABI for the ARM Architecture.std::,set_terminate()std::, in Exception Handling ABI for the ARM Architectureset_unexpected()
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