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Libraries and Floating Point Support Guide

Preface The ARM C and C++ Libraries Mandatory linkage with the C library C and C++ runtime libraries Summary of the C and C++ runtime libraries Compliance with the Application Binary Interface ( Increasing portability of object files to other CL ARM C and C++ library directory structure Selection of ARM C and C++ library variants based Thumb C libraries C and C++ library features C++ and C libraries and the std namespace Multithreaded support in ARM C libraries ARM C libraries and multithreading ARM C libraries and reentrant functions ARM C libraries and thread-safe functions Use of static data in the C libraries Use of the __user_libspace static data area by the C library functions to access subsections of the _ Re-implementation of legacy function __user_libspa Management of locks in multithreaded applications How to ensure re-implemented mutex functions are c Using the ARM C library in a multithreaded environ Thread safety in the ARM C library Thread safety in the ARM C++ library The floating-point status word in a multithreaded Support for building an application with the C lib Using the C library with an application Using the C and C++ libraries with an application Using $Sub$$ to mix semihosted and nonsemihosted I Using the libraries in a nonsemihosting environmen C++ exceptions in a non-semihosting environment Direct semihosting C library function dependencies Indirect semihosting C library function dependenci C library API definitions for targeting a differen Support for building an application without the C Building an application without the C library Creating an application as bare machine C without Integer and floating-point compiler functions and Bare machine integer C Bare machine C with floating-point processing Customized C library startup code and access to C Using low-level functions when exploiting the C li Using high-level functions when exploiting the C l Using malloc() when exploiting the C library Tailoring the C library to a new execution environ Initialization of the execution environment and ex C++ initialization, construction and destruction Exceptions system initialization Emergency buffer memory for exceptions Library functions called from main() Program exit and the assert macro Assembler macros that tailor locale functions in t Link time selection of the locale subsystem in the Runtime selection of the locale subsystem in the C Definition of locale data blocks in the C library LC_CTYPE data block LC_COLLATE data block LC_MONETARY data block LC_NUMERIC data block LC_TIME data block Modification of C library functions for error sign Stack and heap memory allocation and the ARM C and Library heap usage requirements of the ARM C and C Choosing a heap implementation for memory allocati Stack pointer initialization and heap bounds Legacy support for __user_initial_stackheap() Avoiding the heap and heap-using library functions Tailoring input/output functions in the C and C++ Target dependencies on low-level functions in the The C library printf family of functions The C library scanf family of functions Redefining low-level library functions to enable d The C library functions fread(), fgets() and gets( Re-implementing __backspace() in the C library Re-implementing __backspacewc() in the C library Redefining target-dependent system I/O functions i Tailoring non-input/output C library functions Real-time integer division in the ARM libraries ISO C library implementation definition How the ARM C library fulfills ISO C specification mathlib error handling ISO-compliant implementation of signals supported ISO-compliant C library input/output characteristi Standard C++ library implementation definition C library functions and extensions Compiler generated and library-resident helper fun C and C++ library naming conventions Using macro__ARM_WCHAR_NO_IO to disable FILE decla Using library functions with execute-only memory The ARM C Micro-library Floating-point Support The C and C++ Library Functions reference Floating-point Support Functions Reference

LC_CTYPE data block

1.9.4 LC_CTYPE data block

The LC_CTYPE data block configures character classification and conversion.

When defining a locale data block in the C library, the macros that define an LC_CTYPE data block are as follows:
  1. Call LC_CTYPE_begin with a symbol name and a locale name.
  2. Call LC_CTYPE_table repeatedly to specify 256 table entries. LC_CTYPE_table takes a single argument in quotes. This must be a comma-separated list of table entries. Each table entry describes one of the 256 possible characters, and can be either an illegal character (IL) or the bitwise OR of one or more of the following flags:
    __S
    whitespace characters
    __P
    punctuation characters
    __B
    printable space characters
    __L
    lowercase letters
    __U
    uppercase letters
    __N
    decimal digits
    __C
    control characters
    __X
    hexadecimal digit letters A-F and a-f
    __A
    alphabetic but neither uppercase nor lowercase, such as Japanese katakana.

    Note

    A printable space character is defined as any character where the result of both isprint() and isspace() is true.
    __A must not be specified for the same character as either __N or __X.
  3. If required, call one or both of the following optional macros:
    • LC_CTYPE_full_wctype. Calling this macro without arguments causes the C99 wide-character ctype functions (iswalpha(), iswupper(), ...) to return useful values across the full range of Unicode when this LC_CTYPE locale is active. If this macro is not specified, the wide ctype functions treat the first 256 wchar_t values as the same as the 256 char values, and the rest of the wchar_t range as containing illegal characters.
    • LC_CTYPE_multibyte defines this locale to be a multibyte character set. Call this macro with three arguments. The first two arguments are the names of functions that perform conversion between the multibyte character set and Unicode wide characters. The last argument is the value that must be taken by the C macro MB_CUR_MAX for the respective character set. The two function arguments have the following prototypes:
      size_t internal_mbrtowc(wchar_t *pwc, char c, mbstate_t *pstate);
      size_t internal_wcrtomb(char *s, wchar_t w, mbstate_t *pstate);
      
      internal_mbrtowc()
      takes one byte, c, as input, and updates the mbstate_t pointed to by pstate as a result of reading that byte. If the byte completes the encoding of a multibyte character, it writes the corresponding wide character into the location pointed to by pwc, and returns 1 to indicate that it has done so. If not, it returns -2 to indicate the state change of mbstate_t and that no character is output. Otherwise, it returns -1 to indicate that the encoded input is invalid.
      internal_wcrtomb()
      takes one wide character, w, as input, and writes some number of bytes into the memory pointed to by s. It returns the number of bytes output, or -1 to indicate that the input character has no valid representation in the multibyte character set.
  4. Call LC_CTYPE_end, without arguments, to finish the locale block definition.

Example LC_CTYPE data block

        LC_CTYPE_begin utf8_ctype, "UTF-8"
        ;
        ; Single-byte characters in the low half of UTF-8 are exactly
        ; the same as in the normal "C" locale.
        LC_CTYPE_table "__C, __C, __C, __C, __C, __C, __C, __C, __C" ; 0x00-0x08
        LC_CTYPE_table "__C|__S, __C|__S, __C|__S, __C|__S, __C|__S"
                                                         ; 0x09-0x0D(BS,LF,VT,FF,CR)
        LC_CTYPE_table "__C, __C, __C, __C, __C, __C, __C, __C, __C" ; 0x0E-0x16
        LC_CTYPE_table "__C, __C, __C, __C, __C, __C, __C, __C, __C" ; 0x17-0x1F
        LC_CTYPE_table "__B|__S" ; space
        LC_CTYPE_table "__P, __P, __P, __P, __P, __P, __P, __P" ; !"#$%&'(
        LC_CTYPE_table "__P, __P, __P, __P, __P, __P, __P" ; )*+,-./
        LC_CTYPE_table "__N, __N, __N, __N, __N, __N, __N, __N, __N, __N" ; 0-9
        LC_CTYPE_table "__P, __P, __P, __P, __P, __P, __P" ; :;<=>?@
        LC_CTYPE_table "__U|__X, __U|__X, __U|__X, __U|__X, __U|__X, __U|__X" ; A-F
        LC_CTYPE_table "__U, __U, __U, __U, __U, __U, __U, __U, __U, __U" ; G-P
        LC_CTYPE_table "__U, __U, __U, __U, __U, __U, __U, __U, __U, __U" ; Q-Z
        LC_CTYPE_table "__P, __P, __P, __P, __P, __P" ; [\]^_`
        LC_CTYPE_table "__L|__X, __L|__X, __L|__X, __L|__X, __L|__X, __L|__X" ; a-f
        LC_CTYPE_table "__L, __L, __L, __L, __L, __L, __L, __L, __L, __L" ; g-p
        LC_CTYPE_table "__L, __L, __L, __L, __L, __L, __L, __L, __L, __L" ; q-z
        LC_CTYPE_table "__P, __P, __P, __P" ; {|}~
        LC_CTYPE_table "__C" ; 0x7F
        ;
        ; Nothing in the top half of UTF-8 is valid on its own as a
        ; single-byte character, so they are all illegal characters (IL).
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        LC_CTYPE_table "IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL,IL"
        ;
        ; The UTF-8 ctype locale wants the full version of wctype.
        LC_CTYPE_full_wctype
        ;
        ; UTF-8 is a multibyte locale, so we must specify some
        ; conversion functions. MB_CUR_MAX is 6 for UTF-8 (the lead
        ; bytes 0xFC and 0xFD are each followed by five continuation
        ; bytes).
        ;
        ; The implementations of the conversion functions are not
        ; provided in this example.
        ;
        IMPORT  utf8_mbrtowc
        IMPORT  utf8_wcrtomb
        LC_CTYPE_multibyte utf8_mbrtowc, utf8_wcrtomb, 6
        LC_CTYPE_end
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