STRCAT(10.2) STRCAT(10.2)
NAME
strcat, strcmp, strncmp, strcpy, strncpy, strlen, strchr, strrchr,
strdup, strstr - string operations
SYNOPSIS
char* strcat(char *s1, char *s2)
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* strdup(char *s)
char* strstr(char *s1, char *s2)
DESCRIPTION
The arguments s1, s2 and s point to null-terminated strings. The func‐
tions strcat, 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, and 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 lexicographically less than,
equal to, or greater than s2. Strncmp makes the same comparison but
examines at most n 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 if c does not occur in the string. The null
byte terminating a string is considered to be part of the string.
Strdup returns a pointer to a distinct copy of the null-terminated
string s in space obtained from malloc(10.2) or 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.
SOURCE
/libkern/str*.c
/libkern/str*-objtype.c
/lib9/strdup.c
SEE ALSO
memory(10.2), rune(10.2)
BUGS
These routines know nothing about UTF. Use the routines in rune(10.2)
as appropriate. Note, however, that the definition of UTF guarantees
that strcmp compares UTF strings correctly.
The outcome of overlapping moves varies among implementations.
Note the absence of ANSI C's strncat, strpbrk, strspn, strcspn and str‐
tok, but the presence of strdup.
STRCAT(10.2)
