STRCAT(2) STRCAT(2)
NAME
strcat, strncat, strcmp, strncmp, strcpy, strncpy, strlen,
strchr, strrchr, strpbrk, strspn, strcspn, strtok, strdup,
strstr - string operations
SYNOPSIS
char* strcat(char *s1, char *s2)
char* strncat(char *s1, char *s2, long n)
int strcmp(char *s1, char *s2)
int strncmp(char *s1, char *s2, long n)
char* strcpy(char *s1, char *s2)
char* strncpy(char *s1, char *s2, long n)
long strlen(char *s)
char* strchr(char *s, char c)
char* strrchr(char *s, char c)
char* strpbrk(char *s1, char *s2)
long strspn(char *s1, char *s2)
long strcspn(char *s1, char *s2)
char* strtok(char *s1, char *s2)
char* strdup(char *s)
char* strstr(char *s1, char *s2)
DESCRIPTION
The arguments s1, s2 and s point to null-terminated strings.
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 bytes. 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 examines at most n
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STRCAT(2) STRCAT(2)
bytes. The comparisons are made with unsigned bytes.
Strcpy copies string s2 to s1, stopping after the null byte
has been copied. Strncpy copies exactly n bytes, truncating
s2 or adding null bytes 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 bytes in s, not including the
terminating null byte.
Strchr (strrchr) returns a pointer to the first (last)
occurrence of byte c in string s, or `0' if c does not occur
in the string. The null byte terminating a string is con-
sidered to be part of the string.
Strpbrk returns a pointer to the first occurrence in string
s1 of any byte from string s2, `0' if no byte from s2 exists
in s1.
Strspn (strcspn) returns the length of the initial segment
of string s1 which consists entirely of bytes 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
bytes from the separator string s2. The first call, with
pointer s1 specified, returns a pointer to the first byte of
the first token, and will have written a null byte into s1
immediately following the returned token. The function
keeps track of its position in the string between separate
calls; subsequent calls, signified by s1 being `0', will
work through the string s1 immediately following that token.
The separator string s2 may be different from call to call.
When no token remains in s1, `0' is returned.
Strdup returns a pointer to a distinct copy of the null-
terminated string s in space obtained from malloc(2) or `0'
if no space can be obtained.
Strstr returns a pointer to the first occurrence of s2 as a
substring of s1, or 0 if there is none. If s2 is the null
string, strstr returns s1.
SEE ALSO
memory(2), rune(2)
BUGS
These routines know nothing about UTF. Use the routines in
rune(2) as appropriate.
The outcome of overlapping moves varies among
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STRCAT(2) STRCAT(2)
implementations.
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