string(3C) — sys5



STRING(3C)      DOMAIN/IX Reference Manual (SYS5)      STRING(3C)



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

USAGE
     #include <string.h>

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

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

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

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

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

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




Printed 5/10/85                                          STRING-1



STRING(3C)      DOMAIN/IX Reference Manual (SYS5)      STRING(3C)



DESCRIPTION
     The arguments s1, s2 and s point to strings (arrays of char-
     acters 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.
     Strncat appends a maximum of 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 zero, according to whether
     s1 is lexicographically less than, equal to, or greater than
     s2.  Strncmp makes the same comparison, but looks at a max-
     imum of n characters.

     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
     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



STRING-2                                          Printed 5/10/85



STRING(3C)      DOMAIN/IX Reference Manual (SYS5)      STRING(3C)



     NULL pointer is returned.

NOTES
     All these functions are declared in the optional <string.h>
     header file.
     Strcmp and strncmp use native character comparison.  The
     sign of the value returned when one of the characters has
     its high-order bit set is implementation-dependent.

     Character movement is also performed differently in dif-
     ferent implementations.  Overlapping moves may therefore
     yield unexpected results.











































Printed 5/10/85                                          STRING-3

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