1string(9F) Kernel Functions for Drivers string(9F)
2
6 string, strcasecmp, strncasecmp, strncat, strlcat, strchr, strrchr,
7 strcmp, strncmp, strcpy, strncpy, strlcpy, strfree, strspn, strdup,
8 ddi_strdup, strlen, strnlen - string operations
9
11 #include <sys/ddi.h>
12 int strcasecmp(const char *s1, const char *s2);
14 int strncasecmp(const char *s1, const char *s2, size_t n);
17 char *strncat(char * s1, const char * s2, size_t n);
20 size_t strlcat(char *dst, const char *src, size_t dstsize);
23 char *strchr(const char *str, int chr);
26 char *strrchr(const char *str, int chr);
29 int strcmp(const char *s1, const char *s2);
32 int strncmp(const char *s1, const char *s2, size_t n);
35 char *strcpy(char * dst, const char * src);
38 char *strncpy(char * dst, const char * src, size_t n);
41 size_t strlcpy(char *dst, const char *src, size_t dstsize);
44 void strfree(char *s);
47 size_t strspn(const char *s1, const char *s2);
50 char *strdup(const char *s1);
53 char *ddi_strdup(const char *s1, int flag);
56 size_t strlen(const char *s);
59 size_t strnlen(const char *s, size_t n);
62
65 Solaris DDI specific (Solaris DDI).
66
68 The arguments s, s1, and s2 point to strings (arrays of characters ter‐
69 minated by a null character). The strcat(), strncat(), strlcat(), str‐
70 cpy(), strncpy(), strlcpy(), and strfree() functions all alter their
71 first argument. Additionally, the strcpy() function does not check for
72 overflow of the array.
73 strcasecmp(), strncasecmp()
75 The strcasecmp() and strncasecmp() functions are case-insensitive ver‐
76 sions of strcmp() and strncmp() respectively, described below. They
77 assume the ASCII character set and ignore differences in case when com‐
78 paring lower and upper case characters.
79 strncat(), strlcat()
81 The strncat() function appends at most n characters of string s2,
82 including the terminating null character, to the end of string s1. It
83 returns a pointer to the null-terminated result. The initial character
84 of s2 overrides the null character at the end of s1. If copying takes
85 place between objects that overlap, the behavior of strncat()and strl‐
86 cat() is undefined.
87 The strlcat() function appends at most (dstsize-strlen(dst)-1) char‐
90 acters of src to dst (dstsize being the size of the string buffer
91 dst). If the string pointed to by dst contains a null-terminated string
92 that fits into dstsize bytes when strlcat() is called, the string
93 pointed to by dst will be a null-terminated string that fits in dstsize
94 bytes (including the terminating null character) when it completes, and
95 the initial character of src will override the null character at the
96 end of dst. If the string pointed to by dst is longer than dstsize
97 bytes when strlcat() is called, the string pointed to by dst will not
98 be changed. The function returns min{dstsize,strlen(dst)}+strlen(src).
99 Buffer overflow can be checked as follows:
100 if (strlcat(dst, src, dstsize) >= dstsize)
102 return −1;
103 strchr(), strrchr()
106 The strchr() function returns a pointer to the first occurrence of c
107 (converted to a char) in string s, or a null pointer if c does not
108 occur in the string. The strrchr() function returns a pointer to the
109 last occurrence of c. The null character terminating a string is con‐
110 sidered to be part of the string.
111 strcmp(), strncmp()
113 The strcmp() function compares two strings byte-by-byte, according to
114 the ordering of your machine's character set. The function returns an
115 integer greater than, equal to, or less than 0, if the string pointed
116 to by s1 is greater than, equal to, or less than the string pointed to
117 by s2 respectively. The sign of a non-zero return value is determined
118 by the sign of the difference between the values of the first pair of
119 bytes that differ in the strings being compared. The strncmp() function
120 makes the same comparison but looks at a maximum of n bytes. Bytes fol‐
121 lowing a null byte are not compared.
122 strcpy(), strncpy(), strlcpy()
124 The strcpy() function copies string s2 to s1, including the terminating
125 null character, stopping after the null character has been copied. The
126 strncpy() function copies exactly n bytes, truncating s2 or adding null
127 characters to s1 if necessary. The result will not be null-terminated
128 if the length of s2 is n or more. Each function returns s1. If copying
129 takes place between objects that overlap, the behavior of strcpy(),
130 strncpy(), and strlcpy() is undefined.
131 The strlcpy() function copies at most dstsize−1 characters (dstsize
134 being the size of the string buffer dst) from src to dst, truncating
135 src if necessary. The result is always null-terminated. The function
136 returns strlen(src). Buffer overflow can be checked as follows:
137 if (strlcpy(dst, src, dstsize) >= dstsize)
139 return −1;
140 strfree()
143 The strfree() function frees the memory associated with the string
144 pointed to by s. This memory pointed to by s must be of size
145 strlen(s)+1, and must have been allocated (either directly or indi‐
146 rectly) by kmem_alloc(9F) or kmem_zalloc(9F).
147 strspn()
149 The strspn() function returns the length of the initial segment of
150 string s1 that consists entirely of characters from string s2.
151 strdup(), ddi_strdup()
153 The ddi_strdup() function returns a pointer to a new string that is a
154 duplicate of the string pointed to by s1. The returned pointer can be
155 passed to strfree() or kmem_free(9F). The space for the new string is
156 obtained using kmem_alloc(). flag can be either KM_SLEEP or KM_NOSLEEP,
157 and determines whether the caller can sleep for memory. KM_SLEEP allo‐
158 cations may sleep but are guaranteed to succeed. KM_NOSLEEP allocations
159 are guaranteed not to sleep but may fail (return NULL) if no memory is
160 currently available.
161 The strdup() function behaves the same as the ddi_strdup() when called
164 with the KM_SLEEP flag. This means that strdup() can sleep until memory
165 is available and will always succeed.
166 strlen(), strnlen()
168 The strlen() function returns the number of bytes in s, not including
169 the terminating null character.
170 The strnlen() function returns the smaller of n or the number of bytes
173 in s, not including the terminating null character. The strnlen() func‐
174 tion never examines more than n bytes of the string pointed to by s.
175
177 The strdup() and ddi_strdup() functions can be called from user or ker‐
178 nel context.
179 The ddi_strdup() function can be called from interrupt context only if
182 the KM_NOSLEEP flag is set.
183 All the other string manipulation functions can be called from user,
186 interrupt, or kernel context.
187
189 See attributes(5) for descriptions of the following attributes:
190 ┌─────────────────────────────┬─────────────────────────────┐
195 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
196 ├─────────────────────────────┼─────────────────────────────┤
197 │Interface Stability │Committed │
198 └─────────────────────────────┴─────────────────────────────┘
199
201 string(3C), attributes(5), bcopy(9F), ddi_copyin(9F), kmem_alloc(9F)
202 Writing Device Drivers
205
207 If copying takes place between objects that overlap, the behavior of
208 strlcat(), strncat(), strcpy(), strlcpy(), and strncpy() is undefined.
209SunOS 5.11 27 Feb 2009 string(9F)