NAME

string strcat, strncat, strcmp, strncmp, strcpy, strncpy, strlen, index, rindex − string operations

SYNOPSIS

#include <strings.h>

char ∗strcat(s1, s2)
char ∗s1, ∗s2;

char ∗strncat(s1, s2, n)
char ∗s1, ∗s2;

strcmp(s1, s2)
char ∗s1, ∗s2;

strncmp(s1, s2, n)
char ∗s1, ∗s2;

char ∗strcpy(s1, s2)
char ∗s1, ∗s2;

char ∗strncpy(s1, s2, n)
char ∗s1, ∗s2;

strlen(s)
char ∗s;

char ∗index(s, c)
char ∗s, c;

char ∗rindex(s, c)
char ∗s, c;

DESCRIPTION

These functions operate on null-terminated strings.  They do not check for overflow of any receiving string. 

Strcat appends a copy of string s2 to the end of string s1. Strncat copies at most n characters.  Both return a pointer to the null-terminated result. 

Strcmp 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. Strncmp makes the same comparison but looks at at most n characters. 

Strcpy copies string s2 to s1, stopping after the null character has been moved.  Strncpy copies exactly n characters, truncating or null-padding s2; the target may not be null-terminated if the length of s2 is n or more.  Both return s1.

Strlen returns the number of non-null characters in s.

Index (rindex) returns a pointer to the first (last) occurrence of character c in string s, or zero if c does not occur in  the string. 

BUGS

Strcmp uses native character comparison, which is signed on the Sun. 

On the Sun processor (and on some other machines), you can NOT use a zero pointer to indicate a null string.  A zero pointer is an error and results in an abort of the program.  If you wish to indicate a null string, you must have a pointer that points to an explicit null string.  On PDP-11’s and VAX’en, a source pointer of zero (0) can generally be used to indicate a null string.  Programmers using NULL to represent an empty string should be aware of this portability issue. 

Sun Release 3.0β  —  Last change: 19 January 1983