strnicmp() — Compare Substrings Without Case Sensitivity

Format

#include <string.h>
int strnicmp(const char *string1, const char *string2, int n);

Note: The strnset and strset functions are available for C++ programs. They are available for C only when the program defines the __cplusplus__strings__ macro.

Language Level

Extension

Threadsafe

Yes

Locale Sensitive

The behavior of this function might be affected by the LC_CTYPE category of the current locale. For more information, see Understanding CCSIDs and Locales.

Description

The strnicmp() function compares, at most, the first n characters of string1 and string2 without sensitivity to case.

The function operates on null terminated strings. The string arguments to the function are expected to contain a null character (\0) marking the end of the string.

Return Value

The strnicmp() function returns a value indicating the relationship between the substrings, as follows:

Table 1. Return values of `strnicmp()`
Value	Meaning
Less than 0	string1 less than string2
0	string1 equivalent to string2
Greater than 0	string1 greater than string2

Example

This example uses strnicmp() to compare two strings.

#include <stdio.h>
#include <string.h>
int main(void)
{
   char *str1 = "THIS IS THE FIRST STRING";
   char *str2 = "This is the second string";
   int numresult;
     /* Compare the first 11 characters of str1 and str2
        without regard to case                                                */
   numresult = strnicmp(str1, str2, 11);
   if (numresult < 0)
      printf("String 1 is less than string2.\n");
   else
      if (numresult > 0)
         printf("String 1 is greater than string2.\n");
      else
         printf("The two strings are equivalent.\n");
   return 0;
}

The output should be:

      The two strings are equivalent.