STRING(3-BSD) RISC/os Reference Manual STRING(3-BSD)
NAME
strcat, strncat, strcmp, strncmp, strcasecmp, strncasecmp,
strcpy, strncpy, strlen, index, strchr, rindex,
strrchr, strpbrk, strspn, strcspn, strtok - string
operations
SYNOPSIS
#include <strings.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;
int strcasecmp(s1, s2)
char *s1, *s2;
int strncasecmp(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 *index (s, c)
char *s;
int c;
char *strchr (s, c)
char *s;
int c;
char *rindex (s, c)
char *s;
int c;
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STRING(3-BSD) RISC/os Reference Manual STRING(3-BSD)
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 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 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 at most n
characters. strcasecmp and strncasecmp are identical in
function, but are case insensitive. The returned lexico-
graphic difference reflects a conversion to lower-case.
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.
index (rindex) 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.
The routines strchr and strrchr are, respectively, different
names for the index and rindex.
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STRING(3-BSD) RISC/os Reference Manual STRING(3-BSD)
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
NULL pointer is returned.
NOTE
For user convenience, all these functions are declared in
the optional <strings.h> header file.
ERRORS
strcmp and strncmp use native character comparison, which is
signed on PDP-11s and VAX-11s, unsigned on other machines.
Thus the sign of the value returned when one of the charac-
ters has its high-order bit set is implementation-dependent.
Character movement is performed differently in different
implementations. Thus overlapping moves may yield
surprises.
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