15.14 Library functions

Describes implementation-defined aspects of the ARM C compiler and C library relating to library functions, as required by the ISO C standard.

The ISO C library variants are listed in ARM C and C++ Libraries and Floating-Point Support User Guide.
The precise nature of each C library is unique to the particular implementation. The generic ARM C library has, or supports, the following features:
  • The macro NULL expands to the integer constant 0.
  • If a program redefines a reserved external identifier such as printf, an error might occur when the program is linked with the standard libraries. If it is not linked with standard libraries, no error is detected.
  • The __aeabi_assert() function prints details of the failing diagnostic on stderr and then calls the abort() function:
    *** assertion failed: expression, file name, line number


    The behavior of the assert macro depends on the conditions in operation at the most recent occurrence of #include <assert.h>.
For implementation details of mathematical functions, macros, locale, signals, and input/output see ARM C and C++ Libraries and Floating-Point Support User Guide.
Related information
The ARM C and C++ Libraries
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