strcasecmp()

Case-insensitive string comparison

Synopsis:

#include <strings.h>

int strcasecmp( const char* str1,
                const char* str2 );

Library:

libc

Description:

The strcasecmp() function compares two strings, specified by str1 and str2.

Returns:

< 0: s1 is less than s2.
0: s1 is equal to s2.
> 0: s1 is greater than s2.

Examples:

#include <stdio.h>
#include <strings.h>
#include <stdlib.h>

void compare( const char* s1, const char* s2 )
{
    int retval;
    
    retval = strcasecmp( s1, s2 );
    if( retval > 0 ) {
        printf( "%s > %s\n", s1, s2 );
    } else if( retval < 0 ) {
        printf( "%s < %s\n", s1, s2 );
    } else {
        printf( "%s == %s\n", s1, s2 );
    }
}

int main( void )
{
    char* str1 = "abcdefg";
    char* str2 = "HIJ";
    char* str3 = "Abc";
    char* str4 = "aBCDEfg";

    compare( str1, str2 );
    compare( str1, str3 );
    compare( str1, str4 );
    compare( str1, str1 );
    
    compare( str2, str2 );
    compare( str2, str3 );
    compare( str2, str4 );
    compare( str2, str1 );
    
    return EXIT_SUCCESS;
}

This code produces output that looks like:

abcdefg < HIJ
abcdefg > Abc
abcdefg == aBCDEfg
abcdefg == abcdefg
HIJ == HIJ
HIJ > Abc
HIJ > aBCDEfg
HIJ > abcdefg

Classification:

Standard Unix

Safety:
Cancellation point	No
Interrupt handler	Yes
Signal handler	Yes
Thread	Yes