string(3C)             UNIX System V(C Development Set)              string(3C)


NAME
      string: strcat, strdup, strncat, strcmp, strncmp, strcpy, strncpy,
      strlen, strchr, strrchr, strpbrk, strspn, strcspn, strtok, strstr -
      string operations

SYNOPSIS
      #include <string.h>

      char *strcat (char *s1, const char *s2);

      char *strdup (const char *s1);

      char *strncat (char *s1, const char *s2, sizet n);

      int strcmp (const char *s1, const char *s2);

      int strncmp (const char *s1, const char *s2, sizet n);

      char *strcpy (char *s1, const char *s2);

      char *strncpy (char *s1, const char *s2, sizet n);

      sizet strlen (const char *s);

      char *strchr (const char *s, int c);

      char *strrchr (const char *s, int c);

      char *strpbrk (const char *s1, const char *s2);

      sizet strspn (const char *s1, const char *s2);

      sizet strcspn (const char *s1, const char *s2);

      char *strtok (char *s1, const char *s2);

      char *strstr (const char *s1, const char *s2);

DESCRIPTION
      The arguments s, s1, and s2 point to strings (arrays of characters
      terminated by a null character).  The functions strcat, strncat, strcpy,
      strncpy, and strtok.  all alter s1.  These functions do not check for
      overflow of the array pointed to by s1.

      strcat appends a copy of string s2, including the terminating null
      character, to the end of string s1.  strncat appends at most n
      characters.  Each returns a pointer to the null-terminated result.  The
      initial character of s2 overrides the null character at the end of s1.

      strcmp compares its arguments and returns an integer less than, equal to,
      or greater than 0, based upon whether s1 is lexicographically less than,
      equal to, or greater than s2.  strncmp makes the same comparison but


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string(3C)             UNIX System V(C Development Set)              string(3C)


      looks at at most n characters.  Characters following a null character are
      not compared.

      strcpy copies string s2 to s1 including the terminating null character,
      stopping after the null character has been copied.  strncpy copies
      exactly n characters, 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.

      strdup returns a pointer to a new string which is a duplicate of the
      string pointed to by s1.  The space for the new string is obtained using
      malloc(3C).  If the new string can not be created, a NULL pointer is
      returned.

      strlen returns the number of characters in s, not including the
      terminating null character.

      strchr (or strrchr) returns a pointer to the first (last) occurrence of c
      (converted to a char) in string s, or a NULL pointer if c does not occur
      in the string.  The null character terminating a string is considered to
      be part of the string.

      strpbrk returns a pointer to the first occurrence in string s1 of any
      character from string s2, or a NULL pointer if no character from s2
      exists in s1.

      strspn (or strcspn) returns the length of the initial segment of string
      s1 which consists entirely of characters from (not from) string s2.

      strtok considers the string s1 to consist of a sequence of zero or more
      text tokens separated by spans of one or more characters from the
      separator string s2.  The first call (with pointer s1 specified) returns
      a pointer to the first character of the first token, and will have
      written a null character into s1 immediately following the returned
      token. The function keeps track of its position in the string between
      separate calls, so that subsequent calls (which must be made with the
      first argument a NULL pointer) will work through the string s1
      immediately following that token.  In this way subsequent calls will work
      through the string s1 until no tokens remain.  The separator string s2
      may be different from call to call.  When no token remains in s1, a NULL
      pointer is returned.

      strstr locates the first occurrence in string s1 of the sequence of
      characters (excluding the terminating null character) in string s2.
      strstr returns a pointer to the located string, or a null pointer if the
      string is not found. If s2 points to a string with zero length (i.e., the
      string ""), the function returns s1.

SEE ALSO
      malloc(3C), setlocale(3C), strxfrm(3C).




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string(3C)             UNIX System V(C Development Set)              string(3C)


NOTES
      All of these functions assume the default locale ``C.''  For some
      locales, strxfrm should be applied to the strings before they are passed
      to the functions.


















































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