HP-UX Reference (11i v3 07/02) - 3 Library Functions N-Z (vol 7)

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string(3C) string(3C)

strxfrm() offers better performance in, for example, a sorting routine where a number of strings are

each transformed just once and the transformed versions are compared against each other many times.

EXTERNAL INFLUENCES

Locale

The LC_CTYPE category determines the interpretation of the bytes within the string arguments to the

strcoll() and strxfrm() functions as single and/or multibyte characters. It also determines the

case conversions to be done for the

strcasecmp() and strncasecmp() functions.

The

LC_COLLATE category determines the collation ordering used by the

strcoll() and strxfrm()

functions.

International Code Set Support

Single- and multibyte character code sets are supported for the

strcoll() and strxfrm() functions.

All other functions support only single-byte character code sets.

EXAMPLES

The following sample piece of code ﬁnds the tokens, separated by blanks, that are in the string s (assuming

that there are at most

MAXTOK tokens):

int i = 0;

char *s, *last, *tok[MAXTOK];

tok[0] = strtok_r(s, " ", &last);

while (tok[++i] = strtok_r(NULL, " ", &last));

WARNINGS

The functions strcat(), strncat(), strcpy(), strncpy(), strtok(), and strtok_r()

alter the contents of the array to which s1 points. They do not check for overﬂow of the array.

Null pointers for destination strings cause undeﬁned behavior.

Character movement is performed differently in different implementations, so moves involving overlapping

source and destination strings may yield surprises.

The transformed string produced by strxfrm() for a language using an 8-bit code set is usually at least

twice as large as the original string and may be as much four times as large (ordinary characters occupy

two bytes each in the transformed string, 1-to-2 characters four bytes, 2-to-1 characters two bytes per origi-

nal pair, and don’t-care characters no bytes). Each character of a multibyte code set (Asian languages)

occupies three bytes in the transformed string.

For functions strcoll() and strxfrm() results are undeﬁned if the languages speciﬁed by the

LC_COLLATE and LC_CTYPE categories use different code sets.

Users of strtok_r() should also note that the prototype of this function will change in the next release

for conformance with the new POSIX Threads standard.

AUTHOR

string() was developed by the University of California, Berkeley, AT&T, OSF, and HP.