2.11BSD/src/man/man3/string.3

.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)string.3	6.5 (Berkeley) 10/22/87
.\"
.TH STRING 3  "October 22, 1987"
.UC 4
.SH NAME
strcat, strncat, strcmp, strncmp, strcasecmp, strncasecmp, strcpy,
strncpy, strlen, index, rindex \- string operations
.SH SYNOPSIS
.nf
.B #include <strings.h>
.PP
.B char *strcat(s, append)
.B char *s, *append;
.PP
.B char *strncat(s, append, count)
.B char *s, *append;
.B int count;
.PP
.B strcmp(s1, s2)
.B char *s1, *s2;
.PP
.B strncmp(s1, s2, count)
.B char *s1, *s2;
.B int count;
.PP
.B strcasecmp(s1, s2)
.B char *s1, *s2;
.PP
.B strncasecmp(s1, s2, count)
.B char *s1, *s2;
.B int count;
.PP
.B char *strcpy(to, from)
.B char *to, *from;
.PP
.B char *strncpy(to, from, count)
.B char *to, *from;
.B int count;
.PP
.B strlen(s)
.B char *s;
.PP
.B char *index(s, c)
.B char *s, c;
.PP
.B char *rindex(s, c)
.B char *s, c;
.fi
.SH DESCRIPTION
These functions operate on null-terminated strings.
They do not check for overflow of any receiving string.
.PP
\fIStrcat\fP appends a copy of string \fIappend\fP to the end of string
\fIs\fP. \fIStrncat\fP copies at most \fIcount\fP characters.  Both
return a pointer to the null-terminated result.
.PP
\fIStrcmp\fP compares its arguments and returns an integer greater than,
equal to, or less than 0, according as \fIs1\fP is lexicographically
greater than, equal to, or less than \fIs2\fP.  \fIStrncmp\fP makes the
same comparison but looks at at most \fIcount\fP characters.
\fIStrcasecmp\fP and \fIstrncasecmp\fP are identical in function, but are
case insensitive.  The returned lexicographic difference reflects a
conversion to lower-case.
.PP
\fIStrcpy\fP copies string \fIfrom\fP to \fIto\fP, stopping after the
null character has been moved.  \fIStrncpy\fP copies exactly \fIcount\fP
characters, appending nulls if \fIfrom\fP is less than \fIcount\fP
characters in length; the target may not be null-terminated if the
length of \fIfrom\fP is \fIcount\fP or more.  Both return \fIto\fP.
.PP
\fIStrlen\fP returns the number of non-null characters in \fIs\fP.
.PP
.I Index
.RI ( rindex )
returns a pointer to the first (last) occurrence of character 
\fIc\fP in string \fIs\fP or zero if \fIc\fP does not occur in
the string.  Setting \fIc\fP to NULL works.