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utf8len()

Count the bytes in a UTF-8 character

Synopsis:

#include <utf8.h>

int utf8len( const char *s,
             size_t n );

Arguments:

s

A pointer to a UTF-8 character.

n

The maximum number of bytes to count.

Library:

ph

Description:

The utf8str() function counts the number of bytes in the UTF-8 character pointed to by s, to a maximum of n bytes, if n is nonzero.

This function is similar to mblen(), except that:

• utf8str() isn't affected by the current locale.
• The s argument isn't allowed to be NULL.
• You can pass 0 for n if you know that s points to a null-terminated string (i.e. 0 is equivalent to, but more efficient than, strlen(s)).
• utf8str() returns -1 if s points to an invalid byte sequence. If n is nonzero and the n bytes pointed to by s look like an incomplete but potentially valid character, the function returns the negative total length of that (complete) character (this is in the range from -2 to -UTF8_LEN_MAX).

Returns:

0

s points to the null character.

> 0

The number of bytes that comprise the multibyte character (if the next n or fewer bytes form a valid multibyte character).

-1

The n-byte sequence that s points to isn't a valid (beginning of a) UTF-8-encoded character.

Other negative value

The n bytes pointed to by s could be the initial bytes of a valid UTF-8 sequence.

Classification:

Photon

Safety:
Interrupt handler	No
Signal handler	No
Thread	No

See also:

utf8strblen(), utf8strlen(), utf8strnlen()

Unicode Multilingual Support in the Photon Programmer's Guide

mblen() in the QNX Neutrino Library Reference

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