Strings
[C Runtime Library.]

Collaboration diagram for Strings:

---

Detailed Description

C Standard String Library.

Defines
#define	wsize   sizeof(word)
#define	wmask   (wsize - 1)
Typedefs
typedef long	word
	Copy a string.
typedef unsigned char	u_char
Functions
void *	memchr (CONST void *s, int c, size_t n)
	Locate byte in a memory region.
int	memcmp (CONST void *s1, CONST void *s2, size_t n)
	Compare memory regions.
void *	memcpy (void *dst0, CONST void *src0, size_t length)
void *	memset (void *dst, int c, size_t n)
	Fill memory region with a specific byte value.
char *	strcat (char *dst, const char *src)
	Concatenate two strings.
char *	strchr (const char *p, int ch)
	Locate the first occurrence of a character in a string.
int	strcmp (CONST char *s1, CONST char *s2)
	Compare two strings.
char *	strcpy (char *dst, CONST char *src)
	Copy a string.
char *	strdup (CONST char *str)
	Create a copy of a string.
int	stricmp (CONST char *s1, CONST char *s2)
	Compare two strings, ignoring case.
int	strnicmp (CONST char *s1, CONST char *s2, size_t n)
	Compare two strings up to a given number of characters and ignoring case.
size_t	strlen (CONST char *str)
	Compute the length of a NUL terminated string.
char *	strncat (char *dst, CONST char *src, size_t n)
	Concatenate two strings up to a given number of characters.
int	strncmp (const char *s1, const char *s2, size_t n)
	Compare two strings up to a given number of characters.
char *	strncpy (char *dst, CONST char *src, size_t n)
	Copy a string up to a given number of characters.
char *	strrchr (CONST char *p, int ch)
	Locate the last occurrence of a character in a NUL terminated string.
char *	strstr (CONST char *s, CONST char *find)
	Locate a substring in a string.
char *	strtok (char *s, CONST char *delim)
	Isolate sequential tokens in a NUL terminated string.
char *	strtok_r (char *s, const char *delim, char **last)
	Isolate sequential tokens in a NUL terminated string.

---

Typedef Documentation

typedef long word

Copy a string. Copies a source string including the terminating zero character to a destination string. Note: The function does not perform any overflow checking. Parameters: dst  Pointer to the destination string. src  Pointer to the source string. Returns: The original destination pointer.

---

Function Documentation

void* memchr (  CONST void *  s, int  c, size_t  n )

Locate byte in a memory region. This function locates the first occurrence of a byte in a memory region. Parameters: s  Pointer to the start of the memory region. c  The byte to search for, converted to an unsigned character. n  Number of bytes to search. Returns: A pointer to the byte located, or NULL if no such byte exists.

int memcmp (  CONST void *  s1, CONST void *  s2, size_t  n )

Compare memory regions. Both memory regions are assumed to be of equal length. Parameters: s1  Pointer to first memory region. s2  Pointer to second memory region. n  Number of bytes to compare. Returns: Zero if the two regions are identical, otherwise returns the difference between the first two differing bytes.

void* memset (  void *  dst, int  c, size_t  n )

Fill memory region with a specific byte value. Parameters: dst  Pointer to the memory region. c  Byte value. n  Number of bytes. Returns: The original destination pointer.

char* strcat (  char *  dst, const char *  src )

Concatenate two strings. Append a copy of a NUL terminated string to the end of another NUL terminated string. Note: The function does not perform any overflow checking. Parameters: dst  Pointer to the destination string. src  Pointer to the source string. Returns: The original destination pointer.

char* strchr (  const char *  p, int  ch )

Locate the first occurrence of a character in a string. The terminating NUL character is considered part of the string. Parameters: p  Pointer to the string. ch  Character to locate. Returns: A pointer to the located character or NULL if the character does not appear in the string. Examples: uart/uart.c.

int strcmp (  CONST char *  s1, CONST char *  s2 )

Compare two strings. The strings are compared lexicographically. Parameters: s1  Pointer to the first string. s2  Pointer to the second string. Returns: An integer greater than, equal to, or less than 0, according to whether the first string is greater than, equal to, or less than the second string. Examples: httpd/httpserv.c.

char* strcpy (  char *  dst, CONST char *  src )

Copy a string. Copies a source string including the terminating zero character to a destination string. Note: The function does not perform any overflow checking. Parameters: dst  Pointer to the destination string. src  Pointer to the source string. Returns: The original destination pointer. Examples: inetq/inetq.c.

char* strdup (  CONST char *  str  )

Create a copy of a string. Allocates sufficient memory from heap for a copy of the string does the copy. Parameters: str  Pointer to the string to copy. Returns: A pointer to the new string or NULL if allocating memory failed.

int stricmp (  CONST char *  s1, CONST char *  s2 )

Compare two strings, ignoring case. The strings are compared lexicographically. The comparison is done using unsigned characters, Parameters: s1  Pointer to the first string. s2  Pointer to the second string. Returns: An integer greater than, equal to, or less than 0, according to whether the first string is greater than, equal to, or less than the second string after translation of each corresponding character to lower-case.

int strnicmp (  CONST char *  s1, CONST char *  s2, size_t  n )

Compare two strings up to a given number of characters and ignoring case. The strings are compared lexicographically. The comparison is done using unsigned characters, Parameters: s1  Pointer to the first string. s2  Pointer to the second string. n  Number of bytes to compare. Returns: An integer greater than, equal to, or less than 0, according to whether the first string is greater than, equal to, or less than the second string after translation of each corresponding character to lower-case.

size_t strlen (  CONST char *  str  )

Compute the length of a NUL terminated string. Parameters: str  Pointer to the string. Returns: The number of characters that precede the terminating NUL character. Examples: inetq/inetq.c, portdio/portdio.c, and uart/uart.c.

char* strncat (  char *  dst, CONST char *  src, size_t  n )

Concatenate two strings up to a given number of characters. Append a copy of a NUL terminated string to the end of another NUL terminated string. Appends a copy of the source string including the terminating NUL character, if its length is lower than the given number of characters. Otherwise the destination string is left unterminated. Parameters: dst  Pointer to the destination string. src  Pointer to the source string. n  Number of bytes appended at most. Returns: The original destination pointer.

int strncmp (  const char *  s1, const char *  s2, size_t  n )

Compare two strings up to a given number of characters. The strings are compared lexicographically. The comparison is done using unsigned characters, Parameters: s1  Pointer to the first string. s2  Pointer to the second string. n  Number of bytes to compare. Returns: An integer greater than, equal to, or less than 0, according to whether the first string is greater than, equal to, or less than the second string after translation of each corresponding character to lower-case. Examples: portdio/portdio.c, pppc/pppc.c, and tcps/tcps.c.

char* strncpy (  char *  dst, CONST char *  src, size_t  n )

Copy a string up to a given number of characters. Copies a source string including the terminating NUL character, if its length is lower than the given number of characters. Otherwise the destination string is left unterminated. Parameters: dst  Pointer to the destination string. src  Pointer to the source string. n  Maximum number of characters to copy. Returns: The original destination pointer.

char* strrchr (  CONST char *  p, int  ch )

Locate the last occurrence of a character in a NUL terminated string. The terminating NUL character is considered part of the string. Parameters: p  Pointer to the string. ch  Character to locate. Returns: A pointer to the located character or NULL if the character does not appear in the string.

char* strstr (  CONST char *  s, CONST char *  find )

Locate a substring in a string. Finds the first occurrence of a NUL terminated string in another NUL terminated string. Parameters: s  Pointer to the string to be searched. find  Pointer to the string to look for. Returns: A pointer to the first occurrence of the substring. If the string to search is an empty string, then the original pointer is returned. If the substring does not occur in the string to be searched, then a null pointer is returned.

char* strtok (  char *  s, CONST char *  delim )

Isolate sequential tokens in a NUL terminated string. The tokens are separated in the string by at least one of the characters in the given separator string. The first time this function is called, the string should be specified. Subsequent calls, wishing to obtain further tokens from the same string, should pass a null pointer instead. The separator string must be supplied each time, and may change between calls. Parameters: s  Pointer to the string to separate. delim  Pointer to the separator string. Returns: A pointer to the beginning of each subsequent token in the string, after replacing the separator character itself with a zero character. When no more tokens remain, a null pointer is returned.

char* strtok_r (  char *  s, const char *  delim, char **  last )

Isolate sequential tokens in a NUL terminated string. Similar to strtok(), but takes an explicit context argument and thus is reentrant. Parameters: s  Pointer to the string to separate. delim  Pointer to the separator string. last  Used to store the current search context. Returns: A pointer to the beginning of each subsequent token in the string, after replacing the separator character itself with a zero character. When no more tokens remain, a null pointer is returned.

---