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git://sourceware.org/git/newlib-cygwin.git
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ea99f21ce6
By default, Newlib uses a huge object of type struct _reent to store thread-specific data. This object is returned by __getreent() if the __DYNAMIC_REENT__ Newlib configuration option is defined. The reentrancy structure contains for example errno and the standard input, output, and error file streams. This means that if an application only uses errno it has a dependency on the file stream support even if it does not use it. This is an issue for lower end targets and applications which need to qualify the software according to safety standards (for example ECSS-E-ST-40C, ECSS-Q-ST-80C, IEC 61508, ISO 26262, DO-178, DO-330, DO-333). If the new _REENT_THREAD_LOCAL configuration option is enabled, then struct _reent is replaced by dedicated thread-local objects for each struct _reent member. The thread-local objects are defined in translation units which use the corresponding object.
78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/*
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FUNCTION
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<<wctomb>>---minimal wide char to multibyte converter
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INDEX
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wctomb
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SYNOPSIS
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#include <stdlib.h>
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int wctomb(char *<[s]>, wchar_t <[wchar]>);
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DESCRIPTION
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When _MB_CAPABLE is not defined, this is a minimal ANSI-conforming
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implementation of <<wctomb>>. The
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only ``wide characters'' recognized are single bytes,
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and they are ``converted'' to themselves.
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When _MB_CAPABLE is defined, this routine calls <<_wctomb_r>> to perform
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the conversion, passing a state variable to allow state dependent
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decoding. The result is based on the locale setting which may
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be restricted to a defined set of locales.
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Each call to <<wctomb>> modifies <<*<[s]>>> unless <[s]> is a null
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pointer or _MB_CAPABLE is defined and <[wchar]> is invalid.
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RETURNS
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This implementation of <<wctomb>> returns <<0>> if
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<[s]> is <<NULL>>; it returns <<-1>> if _MB_CAPABLE is enabled
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and the wchar is not a valid multi-byte character, it returns <<1>>
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if _MB_CAPABLE is not defined or the wchar is in reality a single
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byte character, otherwise it returns the number of bytes in the
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multi-byte character.
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PORTABILITY
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<<wctomb>> is required in the ANSI C standard. However, the precise
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effects vary with the locale.
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<<wctomb>> requires no supporting OS subroutines.
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*/
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#ifndef _REENT_ONLY
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#include <newlib.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "local.h"
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#ifdef _REENT_THREAD_LOCAL
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_Thread_local _mbstate_t _tls_wctomb_state;
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#endif
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int
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wctomb (char *s,
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wchar_t wchar)
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{
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#ifdef _MB_CAPABLE
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struct _reent *reent = _REENT;
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_REENT_CHECK_MISC(reent);
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return __WCTOMB (reent, s, wchar, &(_REENT_WCTOMB_STATE(reent)));
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#else /* not _MB_CAPABLE */
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if (s == NULL)
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return 0;
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/* Verify that wchar is a valid single-byte character. */
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if ((size_t)wchar >= 0x100) {
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errno = EILSEQ;
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return -1;
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}
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*s = (char) wchar;
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return 1;
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#endif /* not _MB_CAPABLE */
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}
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#endif /* !_REENT_ONLY */
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