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  STRING(3C)      (C Programming Language Utilities)     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;
       sizet n;

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

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

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

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

       int strlen (s)
       char *s;

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



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  STRING(3C)      (C Programming Language Utilities)     STRING(3C)



       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(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
       lexicographically less than, equal to, or greater than s2.
       Strncmp makes the same comparison but looks at at most n
       characters.

       Strcpy copies string s2 to s1, stopping after the null


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  STRING(3C)      (C Programming Language Utilities)     STRING(3C)



       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


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  STRING(3C)      (C Programming Language Utilities)     STRING(3C)



       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 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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