| .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
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| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
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| .\" Formatted or processed versions of this manual, if unaccompanied by |
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| .\" References consulted: |
| .\" Linux libc source code |
| .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) |
| .\" 386BSD man pages |
| .\" Modified Sat Jul 24 18:12:45 1993 by Rik Faith (faith@cs.unc.edu) |
| .TH STRCASECMP 3 2021-03-22 "" "Linux Programmer's Manual" |
| .SH NAME |
| strcasecmp, strncasecmp \- compare two strings ignoring case |
| .SH SYNOPSIS |
| .nf |
| .B #include <strings.h> |
| .PP |
| .BI "int strcasecmp(const char *" s1 ", const char *" s2 ); |
| .BI "int strncasecmp(const char *" s1 ", const char *" s2 ", size_t " n ); |
| .fi |
| .SH DESCRIPTION |
| The |
| .BR strcasecmp () |
| function performs a byte-by-byte comparison of the strings |
| .I s1 |
| and |
| .IR s2 , |
| ignoring the case of the characters. |
| It returns an integer |
| less than, equal to, or greater than zero if |
| .I s1 |
| is found, |
| respectively, to be less than, to match, or be greater than |
| .IR s2 . |
| .PP |
| The |
| .BR strncasecmp () |
| function is similar, except that it compares |
| no more than |
| .I n |
| bytes of |
| .IR s1 |
| and |
| .IR s2 . |
| .SH RETURN VALUE |
| The |
| .BR strcasecmp () |
| and |
| .BR strncasecmp () |
| functions return |
| an integer less than, equal to, or greater than zero if |
| .I s1 |
| is, after ignoring case, found to be |
| less than, to match, or be greater than |
| .IR s2 , |
| respectively. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR strcasecmp (), |
| .BR strncasecmp () |
| T} Thread safety MT-Safe locale |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| 4.4BSD, POSIX.1-2001, POSIX.1-2008. |
| .SH NOTES |
| The |
| .BR strcasecmp () |
| and |
| .BR strncasecmp () |
| functions first appeared in 4.4BSD, where they were declared in |
| .IR <string.h> . |
| Thus, for reasons of historical compatibility, the glibc |
| .I <string.h> |
| header file also declares these functions, if the |
| .B _DEFAULT_SOURCE |
| (or, in glibc 2.19 and earlier, |
| .BR _BSD_SOURCE ) |
| feature test macro is defined. |
| .PP |
| The POSIX.1-2008 standard says of these functions: |
| .PP |
| .RS |
| When the |
| .B LC_CTYPE |
| category of the locale being used is from the POSIX locale, |
| these functions shall behave as if the strings had been converted |
| to lowercase and then a byte comparison performed. |
| Otherwise, the results are unspecified. |
| .RE |
| .SH SEE ALSO |
| .BR bcmp (3), |
| .BR memcmp (3), |
| .BR strcmp (3), |
| .BR strcoll (3), |
| .BR string (3), |
| .BR strncmp (3), |
| .BR wcscasecmp (3), |
| .BR wcsncasecmp (3) |