string(3) Library Functions Manual string(3)
Name
strcasecmp, strncasecmp, strcat, strncat, strcmp, strncmp, strcpy, strncpy, strlen, strchr, strrchr, strpbrk, strspn, strcspn, strstr, str-
tok, index, rindex - string operations
Syntax
#include <strings.h>
or
#include <string.h>
strcasecmp(s1, s2)
char *s1, *s2;
strncasecmp(s1, s2, n)
char *s1, *s2;
char *strcat(s1, s2)
char *s1, *s2;
char *strncat(s1, s2, n)
char *s1, *s2;
int strcmp(s1, s2)
unsigned char *s1, *s2;
int strncmp(s1, s2, n)
unsigned char *s1, *s2;
int n
char *strcpy(s1, s2)
char *s1, *s2;
char *strncpy(s1, s2, n)
char *s1, *s2;
int n
size_t 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;
size_t strspn(s1, s2)
char *s1, *s2;
size_t strcspn(s1, s2)
char *s1, *s2;
char *strtok(s1, s2)
char *s1, *s2;
char *index(s, c)
char *s, c;
char *rindex(s, c)
char *s, c;
char *strstr(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 and subroutines all
alter s1. These functions do not check for overflow of the array pointed to by s1.
The subroutine appends a copy of string s2 to the end of string s1. The subroutine copies at most n characters. Both return a pointer to
the null-terminated result.
The subroutine compares its arguments and returns an integer greater than, equal to, or less than 0, according as s1 is lexicographically
greater than, equal to, or less than s2. The subroutine makes the same comparison but looks at at most n characters. The and subroutines
are identical in function, but are case insensitive. The returned lexicographic difference reflects a conversion to lower-case.
The subroutine copies string s2 to s1, stopping after the null character has been copied. The subroutine 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 subroutine returns the number of characters in s, not including the terminating null character.
The subroutine returns a pointer to the first occurrence of s2 (excluding the terminating null character) in s1, or a NULL pointer if s2
does not occur in s1. If the length of s2 is zero, returns s1.
The ( ) function returns a pointer to the first (last) occurrence of character c in string s, or a NULL pointer is c does not occur in the
string. The null character terminating a string is considered to be part of the string.
The subroutine 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.
The ( ) subroutine returns the length of the initial segment of string s1 which consists entirely of characters from (not from) string s2.
The subroutine 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.
The ( ) subroutine returns a pointer to the first (last) occurrence of character c in string s, or zero if c does not occur in the string.
The <string.h> header file is provided for compatibility with System V; both <string.h> and <strings.h> refer to the same file.
The and subroutines do unsigned character comparisons.
string(3)