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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |ATTRIBUTES |VERSIONS |STANDARDS |HISTORY |NOTES |SEE ALSO |COLOPHON | |
wcstombs(3) Library Functions Manualwcstombs(3)wcstombs - convert a wide-character string to a multibyte string
Standard C library (libc,-lc)
#include <stdlib.h>size_t wcstombs(size_t n;chardest[restrictn], const wchar_t *restrictsrc,size_tn);
Ifdest is not NULL, thewcstombs() function converts the wide- character stringsrc to a multibyte string starting atdest. At mostn bytes are written todest. The sequence of characters placed indest begins in the initial shift state. The conversion can stop for three reasons: • A wide character has been encountered that can not be represented as a multibyte sequence (according to the current locale). In this case,(size_t) -1 is returned. • The length limit forces a stop. In this case, the number of bytes written todest is returned, but the shift state at this point is lost. • The wide-character string has been completely converted, including the terminating null wide character (L'\0'). In this case, the conversion ends in the initial shift state. The number of bytes written todest, excluding the terminating null byte ('\0'), is returned. The programmer must ensure that there is room for at leastn bytes atdest. Ifdest is NULL,n is ignored, and the conversion proceeds as above, except that the converted bytes are not written out to memory, and no length limit exists. In order to avoid the case 2 above, the programmer should make suren is greater than or equal towcstombs(NULL,src,0)+1.Thewcstombs() function returns the number of bytes that make up the converted part of a multibyte sequence, not including the terminating null byte. If a wide character was encountered which could not be converted,(size_t) -1 is returned.
For an explanation of the terms used in this section, seeattributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface│Attribute│Value│ ├──────────────────────────────────────┼───────────────┼─────────┤ │wcstombs() │ Thread safety │ MT-Safe │ └──────────────────────────────────────┴───────────────┴─────────┘
The functionwcsrtombs(3) provides a better interface to the same functionality.
C11, POSIX.1-2008.
POSIX.1-2001, C99.
The behavior ofwcstombs() depends on theLC_CTYPEcategory of the current locale.
mblen(3),mbstowcs(3),mbtowc(3),wcsrtombs(3),wctomb(3)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-06-28wcstombs(3)Pages that refer to this page:MB_CUR_MAX(3), mbstowcs(3), mbtowc(3), wcsrtombs(3), wctomb(3), locale(7)
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