Kernel Functions for Drivers string(9F)
NAME
string, strcasecmp, strncasecmp, strncat, strlcat, strchr,
strrchr, strcmp, strncmp, strcpy, strncpy, strlcpy, strfree,
strspn, strdup, ddistrdup, strlen, strnlen - string opera-
tions
SYNOPSIS
#include
int strcasecmp(const char *s1, const char *s2);
int strncasecmp(const char *s1, const char *s2, sizet n);
char *strncat(char * s1, const char * s2, sizet n);
sizet strlcat(char *dst, const char *src, sizet dstsize);
char *strchr(const char *str, int chr);
char *strrchr(const char *str, int chr);
int strcmp(const char *s1, const char *s2);
int strncmp(const char *s1, const char *s2, sizet n);
char *strcpy(char * dst, const char * src);
char *strncpy(char * dst, const char * src, sizet n);
sizet strlcpy(char *dst, const char *src, sizet dstsize);
void strfree(char *s);
sizet strspn(const char *s1, const char *s2);
char *strdup(const char *s1);
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Kernel Functions for Drivers string(9F)
char *ddistrdup(const char *s1, int flag);
sizet strlen(const char *s);
sizet strnlen(const char *s, sizet n);
INTERFACE LEVEL
Solaris DI specific (Solaris DI).
DESCRIPTION
The arguments s, s1, and s2 point to strings (arrays of
characters terminated by a null character). The strcat(),
strncat(), strlcat(), strcpy(), strncpy(), strlcpy(), and
strfree() functions all alter their first argument. Addi-
tionally, the strcpy() function does not check for overflow
of the array.
strcasecmp(), strncasecmp()
The strcasecmp() and strncasecmp() functions are case-
insensitive versions of strcmp() and strncmp() respec-
tively, described below. They assume the ASCI character
set and ignore differences in case when comparing lower and
upper case characters.
strncat(), strlcat()
The strncat() function appends at most n characters of
string s2, including the terminating null character, to the
end of string s1. It returns a pointer to the null-
terminated result. The initial character of s2 overrides
the null character at the end of s1. If copying takes place
between objects that overlap, the behavior of strncat()and
strlcat() is undefined.
The strlcat() function appends at most (dstsize-
strlen(dst)-1) characters of src to dst (dstsize being the
size of the string buffer dst). If the string pointed to by
dst contains a null-terminated string that fits into dstsize
bytes when strlcat() is called, the string pointed to by dst
will be a null-terminated string that fits in dstsize bytes
(including the terminating null character) when it com-
pletes, and the initial character of src will override the
null character at the end of dst. If the string pointed to
by dst is longer than dstsize bytes when strlcat() is
called, the string pointed to by dst will not be changed.
The function returns min{dstsize,strlen(dst)}]strlen(src).
Buffer overflow can be checked as follows:
if (strlcat(dst, src, dstsize) >= dstsize)
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return -1;
strchr(), strrchr()
The strchr() function returns a pointer to the first
occurrence of c (converted to a char) in string s, or a
null pointer if c does not occur in the string. The
strrchr() function returns a pointer to the last occurrence
of c. The null character terminating a string is considered
to be part of the string.
strcmp(), strncmp()
The strcmp() function compares two strings byte-by-byte,
according to the ordering of your machine's character set.
The 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. The sign of a non-zero return value is deter-
mined by the sign of the difference between the values of
the first pair of bytes that differ in the strings being
compared. The strncmp() function makes the same comparison
but looks at a maximum of n bytes. Bytes following a null
byte are not compared.
strcpy(), strncpy(), strlcpy()
The strcpy() function copies string s2 to s1, including the
terminating null character, stopping after the null charac-
ter has been copied. The strncpy() function copies exactly n
bytes, truncating s2 or adding null characters to s1 if
necessary. The result will not be null-terminated if the
length of s2 is n or more. Each function returns s1. If
copying takes place between objects that overlap, the
behavior of strcpy(), strncpy(), and strlcpy() is undefined.
The strlcpy() function copies at most dstsize-1 characters
(dstsize being the size of the string buffer dst) from src
to dst, truncating src if necessary. The result is always
null-terminated. The function returns strlen(src). Buffer
overflow can be checked as follows:
if (strlcpy(dst, src, dstsize) >= dstsize)
return -1;
strfree()
The strfree() function frees the memory associated with the
string pointed to by s. This memory pointed to by s must be
of size strlen(s)]1, and must have been allocated (either
directly or indirectly) by kmemalloc(9F) or
kmemzalloc(9F).
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strspn()
The strspn() function returns the length of the initial seg-
ment of string s1 that consists entirely of characters from
string s2.
strdup(), ddistrdup()
The ddistrdup() function returns a pointer to a new string
that is a duplicate of the string pointed to by s1. The
returned pointer can be passed to strfree() or
kmemfree(9F). The space for the new string is obtained
using kmemalloc(). flag can be either KMSLEP or
KMNOSLEP, and determines whether the caller can sleep for
memory. KMSLEP allocations may sleep but are guaranteed to
succeed. KMNOSLEP allocations are guaranteed not to sleep
but may fail (return NUL) if no memory is currently avail-
able.
The strdup() function behaves the same as the ddistrdup()
when called with the KMSLEP flag. This means that strdup()
can sleep until memory is available and will always succeed.
strlen(), strnlen()
The strlen() function returns the number of bytes in s, not
including the terminating null character.
The strnlen() function returns the smaller of n or the
number of bytes in s, not including the terminating null
character. The strnlen() function never examines more than n
bytes of the string pointed to by s.
CONTEXT
The strdup() and ddistrdup() functions can be called from
user or kernel context.
The ddistrdup() function can be called from interrupt con-
text only if the KMNOSLEP flag is set.
All the other string manipulation functions can be called
from user, interrupt, or kernel context.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
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Kernel Functions for Drivers string(9F)
ATRIBUTE TYPE ATRIBUTE VALUE
Interface Stability Committed
SEE ALSO
string(3C), attributes(5), bcopy(9F), ddicopyin(9F),
kmemalloc(9F)
Writing Device Drivers
NOTES
If copying takes place between objects that overlap, the
behavior of strlcat(), strncat(), strcpy(), strlcpy(), and
strncpy() is undefined.
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