STRING(3C-SVR4)     RISC/os Reference Manual      STRING(3C-SVR4)



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

SYNOPSIS
     #include <string.h>

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

     char *strdup (const char *s1);

     char *strncat (char *s1, const char *s2, sizet n);

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

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

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

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

     sizet strlen (const char *s);

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

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

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

     sizet strspn (const char *s1, const char *s2);

     sizet strcspn (const char *s1, const char *s2);

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

     char *strstr (const char *s1, const char *s2);

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

     strcat appends a copy of string s2, including the terminat-
     ing null character, to the end of string s1.  strncat
     appends at most n characters.  Each returns a pointer to the
     null-terminated result.  The initial character of s2 over-
     rides the null character at the end of s1.





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     strcmp compares its arguments and returns an integer less
     than, equal to, or greater than 0, based upon whether s1 is
     lexicographically less than, equal to, or greater than s2.
     strncmp makes the same comparison but looks at at most n
     characters.  Characters following a null character are not
     compared.

     strcpy copies string s2 to s1 including the terminating null
     character, 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.

     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, a NULL pointer is returned.

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

     strchr (or strrchr) returns a pointer to the first (last)
     occurrence of c (converted to a char) in string s, or a NULL
     pointer if c does not occur in the string.  The null charac-
     ter 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 (or strcspn) returns the length of the initial seg-
     ment 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
     NULL pointer is returned.





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     strstr locates the first occurrence in string s1 of the
     sequence of characters (excluding the terminating null char-
     acter) in string s2.  strstr returns a pointer to the
     located string, or a null pointer if the string is not
     found. If s2 points to a string with zero length (i.e., the
     string ""), the function returns s1.

SEE ALSO
     malloc(3C), setlocale(3C), strxfrm(3C).

NOTES
     All of these functions assume the default locale C.  For
     some locales, strxfrm should be applied to the strings
     before they are passed to the functions.









































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