string(3P)       INTERACTIVE UNIX System (POSIX)       string(3P)



          NAME
               string: strcat, strdup, strncat, strcmp, strncmp, strcpy,
               strncpy, strlen, strchr, strrchr, strstr, 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 *strstr (s1, s2)
               char *s1, *s2;

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

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



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          string(3P)       INTERACTIVE UNIX System (POSIX)       string(3P)



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

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


















































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          string(3P)       INTERACTIVE UNIX System (POSIX)       string(3P)



          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.

               The function strcat appends a copy of string s2 to the end
               of string s1.

               The function 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(3P).  If the new
               string cannot be created, null is returned.

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

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

               The function 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.

               The function 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.

               strstr returns a pointer to the first occurrence of s2 as a
               substring of s1, or a NULL pointer if s2 does not occur.

               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.

               The function 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


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          string(3P)       INTERACTIVE UNIX System (POSIX)       string(3P)



               the first character of the first token, and will have writ-
               ten 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(3P), malloc(3X).

          CAVEATS
               The functions strcmp and strncmp are implemented by using
               the most natural character comparison on the machine.

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
































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