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     STRING(S)                 UNIX System V                 STRING(S)



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

     Syntax
          #include <string.h>
          #include <sys/types.h>

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

          char *strdup (s1)
          char *s1;

          char *strncat (s1, s2, n)
          char *s1, *s2;
          size_t n;

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

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

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

          char *strncpy (s1, s2, n)
          char *s1, *s2;
          size_t n;

          int strlen (s)
          char *s;

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

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

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

          int strspn (s1, s2)
          char *s1, *s2;

          int strcspn (s1, s2)
          char *s1, *s2;
          char *strtok (s1, s2)
          char *s1, *s2;

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

          strcat appends a copy of string s2 to the end of string 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(S).  If the new string
          cannot be created, null is returned.

          strncat appends at most n characters.  Each returns a
          pointer to the null-terminated result.

          strcmp compares its arguments and returns an integer less
          than, equal to, or greater than 0, according as s1 is
          lexicographically less than, equal to, or greater than s2.
          strncmp makes the same comparison but looks at most n
          characters.

          strcpy copies string s2 to s1, 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.

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

          strchr (strrchr) returns a pointer to the first (last)
          occurrence of character c 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 (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.

          For user convenience, all these functions are declared in
          the optional <string.h> header file.

     See Also
          malloc(S)

     Notes
          strcmp and strncmp are implemented by using the most natural
          character comparison on the machine.  Thus the sign of the
          value returned when one of the characters has its high-order
          bit set is not the same in all implementations and should
          not be relied upon.

          Character movement is performed differently in different
          implementations.  Thus overlapping moves may yield
          surprises.

     Standards Conformance
          strcat, strchr, strcmp, strcpy, strcspn, strlen, strncat,
          strncmp, strpbrk, strspn and strtok are conformant with:
          AT&T SVID Issue 2, Select Code 307-127;
          The X/Open Portability Guide II of January 1987;
          ANSI X3.159-198X C Language Draft Standard, May 13,
          1988;
          IEEE POSIX Std 1003.1-1988 with C Standard Language-
          Dependent System Support;
          and NIST FIPS 151-1.

          strdup is conformant with:
          AT&T SVID Issue 2, Select Code 307-127.

          strncpy and strrchr are conformant with:
          The X/Open Portability Guide II of January 1987;
          ANSI X3.159-198X C Language Draft Standard, May 13, 1988;
          IEEE POSIX Std 1003.1-1988 with C Standard Language-
          Dependent System Support;
          and NIST FIPS 151-1.

                                             (printed 6/20/89)