NAME

       avr_string - <string.h>: Strings

SYNOPSIS

   Macros
       #define _FFS(x)

   Functions
       int ffs (int __val)
       int ffsl (long __val)
       __extension__ int ffsll (long long __val)
       void * memccpy (void *, const void *, int, size_t)
       void * memchr (const void *, int, size_t) __ATTR_PURE__
       int memcmp (const void *, const void *, size_t) __ATTR_PURE__
       void * memcpy (void *, const void *, size_t)
       void * memmem (const void *, size_t, const void *, size_t) __ATTR_PURE__
       void * memmove (void *, const void *, size_t)
       void * memrchr (const void *, int, size_t) __ATTR_PURE__
       void * memset (void *, int, size_t)
       char * strcat (char *, const char *)
       char * strchr (const char *, int) __ATTR_PURE__
       char * strchrnul (const char *, int) __ATTR_PURE__
       int strcmp (const char *, const char *) __ATTR_PURE__
       char * strcpy (char *, const char *)
       int strcasecmp (const char *, const char *) __ATTR_PURE__
       char * strcasestr (const char *, const char *) __ATTR_PURE__
       size_t strcspn (const char *__s, const char *__reject) __ATTR_PURE__
       char * strdup (const char *s1)
       size_t strlcat (char *, const char *, size_t)
       size_t strlcpy (char *, const char *, size_t)
       size_t strlen (const char *) __ATTR_PURE__
       char * strlwr (char *)
       char * strncat (char *, const char *, size_t)
       int strncmp (const char *, const char *, size_t) __ATTR_PURE__
       char * strncpy (char *, const char *, size_t)
       int strncasecmp (const char *, const char *, size_t) __ATTR_PURE__
       size_t strnlen (const char *, size_t) __ATTR_PURE__
       char * strpbrk (const char *__s, const char *__accept) __ATTR_PURE__
       char * strrchr (const char *, int) __ATTR_PURE__
       char * strrev (char *)
       char * strsep (char **, const char *)
       size_t strspn (const char *__s, const char *__accept) __ATTR_PURE__
       char * strstr (const char *, const char *) __ATTR_PURE__
       char * strtok (char *, const char *)
       char * strtok_r (char *, const char *, char **)
       char * strupr (char *)

Detailed Description

       #include <string.h>

       The string functions perform string operations on NULL terminated strings.

       Note
           If the strings you are working on resident in program space (flash), you will need to
           use the string functions described in <avr/pgmspace.h>: Program Space Utilities.

Macro Definition Documentation

   #define _FFS(x)
       This macro finds the first (least significant) bit set in the input value.

       This macro is very similar to the function ffs() except that it evaluates its argument at
       compile-time, so it should only be applied to compile-time constant expressions where it
       will reduce to a constant itself. Application of this macro to expressions that are not
       constant at compile-time is not recommended, and might result in a huge amount of code
       generated.

       Returns
           The _FFS() macro returns the position of the first (least significant) bit set in the
           word val, or 0 if no bits are set. The least significant bit is position 1. Only 16
           bits of argument are evaluted.

Function Documentation

   int ffs (int val)
       This function finds the first (least significant) bit set in the input value.

       Returns
           The ffs() function returns the position of the first (least significant) bit set in
           the word val, or 0 if no bits are set. The least significant bit is position 1.

       Note
           For expressions that are constant at compile time, consider using the _FFS macro
           instead.

   int ffsl (long __val)
       Same as ffs(), for an argument of type long.

   int ffsll (long long __val)
       Same as ffs(), for an argument of type long long.

   void * memccpy (void * dest, const void * src, int val, size_t len)
       Copy memory area. The memccpy() function copies no more than len bytes from memory area
       src to memory area dest, stopping when the character val is found.

       Returns
           The memccpy() function returns a pointer to the next character in dest after val, or
           NULL if val was not found in the first len characters of src.

   void * memchr (const void * src, int val, size_t len)
       Scan memory for a character. The memchr() function scans the first len bytes of the memory
       area pointed to by src for the character val. The first byte to match val (interpreted as
       an unsigned character) stops the operation.

       Returns
           The memchr() function returns a pointer to the matching byte or NULL if the character
           does not occur in the given memory area.

   int memcmp (const void * s1, const void * s2, size_t len)
       Compare memory areas. The memcmp() function compares the first len bytes of the memory
       areas s1 and s2. The comparision is performed using unsigned char operations.

       Returns
           The memcmp() function returns an integer less than, equal to, or greater than zero if
           the first len bytes of s1 is found, respectively, to be less than, to match, or be
           greater than the first len bytes of s2.

       Note
           Be sure to store the result in a 16 bit variable since you may get incorrect results
           if you use an unsigned char or char due to truncation.

       Warning
           This function is not -mint8 compatible, although if you only care about testing for
           equality, this function should be safe to use.

   void * memcpy (void * dest, const void * src, size_t len)
       Copy a memory area. The memcpy() function copies len bytes from memory area src to memory
       area dest. The memory areas may not overlap. Use memmove() if the memory areas do overlap.

       Returns
           The memcpy() function returns a pointer to dest.

   void * memmem (const void * s1, size_t len1, const void * s2, size_t len2)
       The memmem() function finds the start of the first occurrence of the substring s2 of
       length len2 in the memory area s1 of length len1.

       Returns
           The memmem() function returns a pointer to the beginning of the substring, or NULL if
           the substring is not found. If len2 is zero, the function returns s1.

   void * memmove (void * dest, const void * src, size_t len)
       Copy memory area. The memmove() function copies len bytes from memory area src to memory
       area dest. The memory areas may overlap.

       Returns
           The memmove() function returns a pointer to dest.

   void * memrchr (const void * src, int val, size_t len)
       The memrchr() function is like the memchr() function, except that it searches backwards
       from the end of the len bytes pointed to by src instead of forwards from the front.
       (Glibc, GNU extension.)

       Returns
           The memrchr() function returns a pointer to the matching byte or NULL if the character
           does not occur in the given memory area.

   void * memset (void * dest, int val, size_t len)
       Fill memory with a constant byte. The memset() function fills the first len bytes of the
       memory area pointed to by dest with the constant byte val.

       Returns
           The memset() function returns a pointer to the memory area dest.

   int strcasecmp (const char * s1, const char * s2)
       Compare two strings ignoring case. The strcasecmp() function compares the two strings s1
       and s2, ignoring the case of the characters.

       Returns
           The strcasecmp() function returns an integer less than, equal to, or greater than zero
           if s1 is found, respectively, to be less than, to match, or be greater than s2. A
           consequence of the ordering used by strcasecmp() is that if s1 is an initial substring
           of s2, then s1 is considered to be 'less than' s2.

   char * strcasestr (const char * s1, const char * s2)
       The strcasestr() function finds the first occurrence of the substring s2 in the string s1.
       This is like strstr(), except that it ignores case of alphabetic symbols in searching for
       the substring. (Glibc, GNU extension.)

       Returns
           The strcasestr() function returns a pointer to the beginning of the substring, or NULL
           if the substring is not found. If s2 points to a string of zero length, the function
           returns s1.

   char * strcat (char * dest, const char * src)
       Concatenate two strings. The strcat() function appends the src string to the dest string
       overwriting the '\0' character at the end of dest, and then adds a terminating '\0'
       character. The strings may not overlap, and the dest string must have enough space for the
       result.

       Returns
           The strcat() function returns a pointer to the resulting string dest.

   char * strchr (const char * src, int val)
       Locate character in string. The strchr() function returns a pointer to the first
       occurrence of the character val in the string src.

       Here 'character' means 'byte' - these functions do not work with wide or multi-byte
       characters.

       Returns
           The strchr() function returns a pointer to the matched character or NULL if the
           character is not found.

   char * strchrnul (const char * s, int c)
       The strchrnul() function is like strchr() except that if c is not found in s, then it
       returns a pointer to the null byte at the end of s, rather than NULL. (Glibc, GNU
       extension.)

       Returns
           The strchrnul() function returns a pointer to the matched character, or a pointer to
           the null byte at the end of s (i.e., s+strlen(s)) if the character is not found.

   int strcmp (const char * s1, const char * s2)
       Compare two strings. The strcmp() function compares the two strings s1 and s2.

       Returns
           The strcmp() function returns an integer less than, equal to, or greater than zero if
           s1 is found, respectively, to be less than, to match, or be greater than s2. A
           consequence of the ordering used by strcmp() is that if s1 is an initial substring of
           s2, then s1 is considered to be 'less than' s2.

   char * strcpy (char * dest, const char * src)
       Copy a string. The strcpy() function copies the string pointed to by src (including the
       terminating '\0' character) to the array pointed to by dest. The strings may not overlap,
       and the destination string dest must be large enough to receive the copy.

       Returns
           The strcpy() function returns a pointer to the destination string dest.

       Note
           If the destination string of a strcpy() is not large enough (that is, if the
           programmer was stupid/lazy, and failed to check the size before copying) then anything
           might happen. Overflowing fixed length strings is a favourite cracker technique.

   size_t strcspn (const char * s, const char * reject)
       The strcspn() function calculates the length of the initial segment of s which consists
       entirely of characters not in reject.

       Returns
           The strcspn() function returns the number of characters in the initial segment of s
           which are not in the string reject. The terminating zero is not considered as a part
           of string.

   char * strdup (const char * s1)
       Duplicate a string. The strdup() function allocates memory and copies into it the string
       addressed by s1, including the terminating null character.

       Warning
           The strdup() function calls malloc() to allocate the memory for the duplicated string!
           The user is responsible for freeing the memory by calling free().

       Returns
           The strdup() function returns a pointer to the resulting string dest. If malloc()
           cannot allocate enough storage for the string, strdup() will return NULL.

       Warning
           Be sure to check the return value of the strdup() function to make sure that the
           function has succeeded in allocating the memory!

   size_t strlcat (char * dst, const char * src, size_t siz)
       Concatenate two strings. Appends src to string dst of size siz (unlike strncat(), siz is
       the full size of dst, not space left). At most siz-1 characters will be copied. Always
       NULL terminates (unless siz <= strlen(dst)).

       Returns
           The strlcat() function returns strlen(src) + MIN(siz, strlen(initial dst)). If retval
           >= siz, truncation occurred.

       Appends src to string dst of size siz (unlike strncat(), siz is the full size of dst, not
       space left). At most siz-1 characters will be copied. Always NULL terminates (unless siz
       <= strlen(dst)).

       Returns
           The strlcat() function returns strlen(src) + MIN(siz, strlen(initial dst)). If retval
           >= siz, truncation occurred.

   size_t strlcpy (char * dst, const char * src, size_t siz)
       Copy a string. Copy src to string dst of size siz. At most siz-1 characters will be
       copied. Always NULL terminates (unless siz == 0).

       Returns
           The strlcpy() function returns strlen(src). If retval >= siz, truncation occurred.

       Copy src to string dst of size siz. At most siz-1 characters will be copied. Always NULL
       terminates (unless siz == 0).

       Returns
           The strlcpy() function returns strlen(src). If retval >= siz, truncation occurred.

   size_t strlen (const char * src)
       Calculate the length of a string. The strlen() function calculates the length of the
       string src, not including the terminating '\0' character.

       Returns
           The strlen() function returns the number of characters in src.

   char * strlwr (char * s)
       Convert a string to lower case. The strlwr() function will convert a string to lower case.
       Only the upper case alphabetic characters [A .. Z] are converted. Non-alphabetic
       characters will not be changed.

       Returns
           The strlwr() function returns a pointer to the converted string.

   int strncasecmp (const char * s1, const char * s2, size_t len)
       Compare two strings ignoring case. The strncasecmp() function is similar to strcasecmp(),
       except it only compares the first len characters of s1.

       Returns
           The strncasecmp() function returns an integer less than, equal to, or greater than
           zero if s1 (or the first len bytes thereof) is found, respectively, to be less than,
           to match, or be greater than s2. A consequence of the ordering used by strncasecmp()
           is that if s1 is an initial substring of s2, then s1 is considered to be 'less than'
           s2.

   char * strncat (char * dest, const char * src, size_t len)
       Concatenate two strings. The strncat() function is similar to strcat(), except that only
       the first n characters of src are appended to dest.

       Returns
           The strncat() function returns a pointer to the resulting string dest.

   int strncmp (const char * s1, const char * s2, size_t len)
       Compare two strings. The strncmp() function is similar to strcmp(), except it only
       compares the first (at most) n characters of s1 and s2.

       Returns
           The strncmp() function returns an integer less than, equal to, or greater than zero if
           s1 (or the first n bytes thereof) is found, respectively, to be less than, to match,
           or be greater than s2.

   char * strncpy (char * dest, const char * src, size_t len)
       Copy a string. The strncpy() function is similar to strcpy(), except that not more than n
       bytes of src are copied. Thus, if there is no null byte among the first n bytes of src,
       the result will not be null-terminated.

       In the case where the length of src is less than that of n, the remainder of dest will be
       padded with nulls.

       Returns
           The strncpy() function returns a pointer to the destination string dest.

   size_t strnlen (const char * src, size_t len)
       Determine the length of a fixed-size string. The strnlen function returns the number of
       characters in the string pointed to by src, not including the terminating '\0' character,
       but at most len. In doing this, strnlen looks only at the first len characters at src and
       never beyond src+len.

       Returns
           The strnlen function returns strlen(src), if that is less than len, or len if there is
           no '\0' character among the first len characters pointed to by src.

   char * strpbrk (const char * s, const char * accept)
       The strpbrk() function locates the first occurrence in the string s of any of the
       characters in the string accept.

       Returns
           The strpbrk() function returns a pointer to the character in s that matches one of the
           characters in accept, or NULL if no such character is found. The terminating zero is
           not considered as a part of string: if one or both args are empty, the result will be
           NULL.

   char * strrchr (const char * src, int val)
       Locate character in string. The strrchr() function returns a pointer to the last
       occurrence of the character val in the string src.

       Here 'character' means 'byte' - these functions do not work with wide or multi-byte
       characters.

       Returns
           The strrchr() function returns a pointer to the matched character or NULL if the
           character is not found.

   char * strrev (char * s)
       Reverse a string. The strrev() function reverses the order of the string.

       Returns
           The strrev() function returns a pointer to the beginning of the reversed string.

   char * strsep (char ** sp, const char * delim)
       Parse a string into tokens. The strsep() function locates, in the string referenced by
       *sp, the first occurrence of any character in the string delim (or the terminating '\0'
       character) and replaces it with a '\0'. The location of the next character after the
       delimiter character (or NULL, if the end of the string was reached) is stored in *sp. An
       ``empty'' field, i.e. one caused by two adjacent delimiter characters, can be detected by
       comparing the location referenced by the pointer returned in *sp to '\0'.

       Returns
           The strsep() function returns a pointer to the original value of *sp. If *sp is
           initially NULL, strsep() returns NULL.

   size_t strspn (const char * s, const char * accept)
       The strspn() function calculates the length of the initial segment of s which consists
       entirely of characters in accept.

       Returns
           The strspn() function returns the number of characters in the initial segment of s
           which consist only of characters from accept. The terminating zero is not considered
           as a part of string.

   char * strstr (const char * s1, const char * s2)
       Locate a substring. The strstr() function finds the first occurrence of the substring s2
       in the string s1. The terminating '\0' characters are not compared.

       Returns
           The strstr() function returns a pointer to the beginning of the substring, or NULL if
           the substring is not found. If s2 points to a string of zero length, the function
           returns s1.

   char * strtok (char * s, const char * delim)
       Parses the string s into tokens. strtok parses the string s into tokens. The first call to
       strtok should have s as its first argument. Subsequent calls should have the first
       argument set to NULL. If a token ends with a delimiter, this delimiting character is
       overwritten with a '\0' and a pointer to the next character is saved for the next call to
       strtok. The delimiter string delim may be different for each call.

       Returns
           The strtok() function returns a pointer to the next token or NULL when no more tokens
           are found.

       Note
           strtok() is NOT reentrant. For a reentrant version of this function see strtok_r().

   char * strtok_r (char * string, const char * delim, char ** last)
       Parses string into tokens. strtok_r parses string into tokens. The first call to strtok_r
       should have string as its first argument. Subsequent calls should have the first argument
       set to NULL. If a token ends with a delimiter, this delimiting character is overwritten
       with a '\0' and a pointer to the next character is saved for the next call to strtok_r.
       The delimiter string delim may be different for each call. last is a user allocated char*
       pointer. It must be the same while parsing the same string. strtok_r is a reentrant
       version of strtok().

       Returns
           The strtok_r() function returns a pointer to the next token or NULL when no more
           tokens are found.

   char * strupr (char * s)
       Convert a string to upper case. The strupr() function will convert a string to upper case.
       Only the lower case alphabetic characters [a .. z] are converted. Non-alphabetic
       characters will not be changed.

       Returns
           The strupr() function returns a pointer to the converted string. The pointer is the
           same as that passed in since the operation is perform in place.

Author

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