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mbrlen.3p (4295B)

    

  1. '\" et
  2. .TH MBRLEN "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
  3. .\"
  4. .SH PROLOG
  5. This manual page is part of the POSIX Programmer's Manual.
  6. The Linux implementation of this interface may differ (consult
  7. the corresponding Linux manual page for details of Linux behavior),
  8. or the interface may not be implemented on Linux.
  9. .\"
  10. .SH NAME
  11. mbrlen
  12. \(em get number of bytes in a character (restartable)
  13. .SH SYNOPSIS
  14. .LP
  15. .nf
  16. #include <wchar.h>
  17. .P
  18. size_t mbrlen(const char *restrict \fIs\fP, size_t \fIn\fP,
  19.     mbstate_t *restrict \fIps\fP);
  20. .fi
  21. .SH DESCRIPTION
  22. The functionality described on this reference page is aligned with the
  23. ISO\ C standard. Any conflict between the requirements described here and the
  24. ISO\ C standard is unintentional. This volume of POSIX.1\(hy2017 defers to the ISO\ C standard.
  25. .P
  26. If
  27. .IR s
  28. is not a null pointer,
  29. \fImbrlen\fR()
  30. shall determine the number of bytes constituting the character pointed
  31. to by
  32. .IR s .
  33. It shall be equivalent to:
  34. .sp
  35. .RS 4
  36. .nf
  38. mbstate_t internal;
  39. mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);
  40. .fi
  41. .P
  42. .RE
  43. .P
  44. If
  45. .IR ps
  46. is a null pointer, the
  47. \fImbrlen\fR()
  48. function shall use its own internal
  49. .BR mbstate_t
  50. object, which is initialized at program start-up to the initial
  51. conversion state. Otherwise, the
  52. .BR mbstate_t
  53. object pointed to by
  54. .IR ps
  55. shall be used to completely describe the current conversion state of
  56. the associated character sequence. The implementation shall behave as
  57. if no function defined in this volume of POSIX.1\(hy2017 calls
  58. \fImbrlen\fR().
  59. .P
  60. The behavior of this function is affected by the
  61. .IR LC_CTYPE
  62. category of the current locale.
  63. .P
  64. The
  65. \fImbrlen\fR()
  66. function need not be thread-safe if called with a NULL
  67. .IR ps
  68. argument.
  69. .P
  70. The
  71. \fImbrlen\fR()
  72. function shall not change the setting of
  73. .IR errno
  74. if successful.
  75. .SH "RETURN VALUE"
  76. The
  77. \fImbrlen\fR()
  78. function shall return the first of the following that applies:
  79. .IP 0 12
  80. If the next
  81. .IR n
  82. or fewer bytes complete the character that corresponds to the null
  83. wide character.
  84. .IP "\fIpositive\fP" 12
  85. If the next
  86. .IR n
  87. or fewer bytes complete a valid character; the value returned shall
  88. be the number of bytes that complete the character.
  89. .IP "(\fBsize_t\fP)\-2" 12
  90. If the next
  91. .IR n
  92. bytes contribute to an incomplete but potentially valid character, and
  93. all
  94. .IR n
  95. bytes have been processed. When
  96. .IR n
  97. has at least the value of the
  98. {MB_CUR_MAX}
  99. macro, this case can only occur if
  100. .IR s
  101. points at a sequence of redundant shift sequences (for implementations
  102. with state-dependent encodings).
  103. .IP "(\fBsize_t\fP)\-1" 12
  104. If an encoding error occurs, in which case the next
  105. .IR n
  106. or fewer bytes do not contribute to a complete and valid character. In
  107. this case,
  108. .BR [EILSEQ] 
  109. shall be stored in
  110. .IR errno
  111. and the conversion state is undefined.
  112. .SH ERRORS
  113. The
  114. \fImbrlen\fR()
  115. function shall fail if:
  116. .TP
  117. .BR EILSEQ
  118. An invalid character sequence is detected.
  119. In the POSIX locale an
  120. .BR [EILSEQ] 
  121. error cannot occur since all byte values are valid characters.
  122. .br
  123. .P
  124. The
  125. \fImbrlen\fR()
  126. function may fail if:
  127. .TP
  128. .BR EINVAL
  129. .IR ps
  130. points to an object that contains an invalid conversion state.
  131. .LP
  132. .IR "The following sections are informative."
  133. .SH EXAMPLES
  134. None.
  135. .SH "APPLICATION USAGE"
  136. None.
  137. .SH RATIONALE
  138. None.
  139. .SH "FUTURE DIRECTIONS"
  140. None.
  141. .SH "SEE ALSO"
  142. .IR "\fImbsinit\fR\^(\|)",
  143. .IR "\fImbrtowc\fR\^(\|)"
  144. .P
  145. The Base Definitions volume of POSIX.1\(hy2017,
  146. .IR "\fB<wchar.h>\fP"
  147. .\"
  148. .SH COPYRIGHT
  149. Portions of this text are reprinted and reproduced in electronic form
  150. from IEEE Std 1003.1-2017, Standard for Information Technology
  151. -- Portable Operating System Interface (POSIX), The Open Group Base
  152. Specifications Issue 7, 2018 Edition,
  153. Copyright (C) 2018 by the Institute of
  154. Electrical and Electronics Engineers, Inc and The Open Group.
  155. In the event of any discrepancy between this version and the original IEEE and
  156. The Open Group Standard, the original IEEE and The Open Group Standard
  157. is the referee document. The original Standard can be obtained online at
  158. http://www.opengroup.org/unix/online.html .
  159. .PP
  160. Any typographical or formatting errors that appear
  161. in this page are most likely
  162. to have been introduced during the conversion of the source files to
  163. man page format. To report such errors, see
  164. https://www.kernel.org/doc/man-pages/reporting_bugs.html .