U8_STRCMP(3C)U8_STRCMP(3C)NAMEu8_strcmp - UTF-8 string comparison function
SYNOPSIS
#include <sys/u8_textprep.h>
int u8_strcmp(const char *s1, const char *s2, size_t n,
int flag, size_t version, int *errnum);
PARAMETERS
s1, s2
Pointers to null-terminated UTF-8 strings
n
The maximum number of bytes to be compared. If 0, the
comparison is performed until either or both of the
strings are examined to the string terminating null byte.
flag
The possible comparison options constructed by a bit-wise-
inclusive-OR of the following values:
U8_STRCMP_CS
Perform case-sensitive string comparison. This is the
default.
U8_STRCMP_CI_UPPER
Perform case-insensitive string comparison based on
Unicode upper case converted results of s1 and s2.
U8_STRCMP_CI_LOWER
Perform case-insensitive string comparison based on
Unicode lower case converted results of s1 and s2.
U8_STRCMP_NFD
Perform string comparison after s1 and s2 have been
normalized by using Unicode Normalization Form D.
U8_STRCMP_NFC
Perform string comparison after s1 and s2 have been
normalized by using Unicode Normalization Form C.
U8_STRCMP_NFKD
Perform string comparison after s1 and s2 have been
normalized by using Unicode Normalization Form KD.
U8_STRCMP_NFKC
Perform string comparison after s1 and s2 have been
normalized by using Unicode Normalization Form KC.
Only one case-sensitive or case-insensitive option is
allowed. Only one Unicode Normalization option is allowed.
version
The version of Unicode data that should be used during
comparison. The following values are supported:
U8_UNICODE_320
Use Unicode 3.2.0 data during comparison.
U8_UNICODE_500
Use Unicode 5.0.0 data during comparison.
U8_UNICODE_LATEST
Use the latest Unicode version data available, which
is Unicode 5.0.0.
errnum
A non-zero value indicates that an error has occurred dur‐
ing comparison. The following values are supported:
EBADF
The specified option values are conflicting and
cannot be supported.
EILSEQ
There was an illegal character at s1, s2, or
both.
EINVAL
There was an incomplete character at s1, s2, or
both.
ERANGE
The specified Unicode version value is not sup‐
ported.
DESCRIPTION
The u8_stcmp() function internally processes UTF-8 strings pointed to
by s1 and s2 based on the corresponding version of the Unicode Standard
and other input arguments and compares the result strings in byte-by-
byte, machine ordering.
When multiple comparison options are specified, Unicode Normalization
is performed after case-sensitive or case-insensitive processing is
performed.
RETURN VALUES
The u8_strcmp() function returns an integer greater than, equal to, or
less than 0 if the string pointed to by s1 is greater than, equal to,
or less than the string pointed to by s2, respectively.
When u8_strcmp() detects an illegal or incomplete character, such char‐
acter causes the function to set errnum to indicate the error. After‐
ward, the comparison is still performed on the resultant strings and a
value based on byte-by-byte comparison is always returned.
EXAMPLES
Example 1 Perform simple default string comparison.
#include <sys/u8_textprep.h>
int
docmp_default(const char *u1, const char *u2) {
int result;
int errnum;
result = u8_strcmp(u1, u2, 0, 0, U8_UNICODE_LATEST, &errnum);
if (errnum == EILSEQ)
return (-1);
if (errnum == EINVAL)
return (-2);
if (errnum == EBADF)
return (-3);
if (errnum == ERANGE)
return (-4);
Example 2 Perform upper case based case-insensitive comparison with
Unicode 3.2.0 date.
#include <sys/u8_textprep.h>
int
docmp_caseinsensitive_u320(const char *u1, const char *u2) {
int result;
int errnum;
result = u8_strcmp(u1, u2, 0, U8_STRCMP_CI_UPPER,
U8_UNICODE_320, &errnum);
if (errnum == EILSEQ)
return (-1);
if (errnum == EINVAL)
return (-2);
if (errnum == EBADF)
return (-3);
if (errnum == ERANGE)
return (-4);
return (result);
}
Example 3 Perform Unicode Normalization Form D.
Perform Unicode Normalization Form D and upper case based case-insensi‐
tive comparison with Unicode 3.2.0 date.
#include <sys/u8_textprep.h>
int
docmp_nfd_caseinsensitive_u320(const char *u1, const char *u2) {
int result;
int errnum;
result = u8_strcmp(u1, u2, 0,
(U8_STRCMP_NFD|U8_STRCMP_CI_UPPER), U8_UNICODE_320,
&errnum);
if (errnum == EILSEQ)
return (-1);
if (errnum == EINVAL)
return (-2);
if (errnum == EBADF)
return (-3);
if (errnum == ERANGE)
return (-4);
return (result);
}
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Committed │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOu8_textprep_str(3C), u8_validate(3C), attributes(5), u8_strcmp(9F),
u8_textprep_str(9F), u8_validate(9F)
The Unicode Standard (http://www.unicode.org)
Sep 12, 2007 U8_STRCMP(3C)
