STRING(3C)           INTERACTIVE UNIX System           STRING(3C)



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

          SYNOPSIS
               #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;



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





















































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          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 dupli-
               cate 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, 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 lexi-
               cographically less than, equal to, or greater than s2.
               Strncmp makes the same comparison but looks at most n char-
               acters.

               Strcpy copies string s2 to s1, stopping after the null char-
               acter 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 ter-
               minating 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


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               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 dif-
               ferent 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(3C), malloc(3X).

          CAVEATS
               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.
































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