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Windows NT
Import Library
Header File
Platform Notes


The lstrcmpi function compares two character strings. The comparison is not case sensitive.

int lstrcmpi(

LPCTSTR lpString1,
// address of first string
LPCTSTR lpString2
// address of second string



Points to the first null-terminated string to be compared.


Points to the second null-terminated string to be compared.

Return Values

If the function succeeds and the string pointed to by lpString1 is less than the string pointed to by lpString2, the return value is negative; if the string pointed to by lpString1 is greater than the string pointed to by lpString2, it is positive. If the strings are equal, the return value is zero.


The lstrcmpi function compares two strings by checking the first characters against each other, the second characters against each other, and so on until it finds an inequality or reaches the ends of the strings.

The function returns the difference of the values of the first unequal characters it encounters. For example, lstrcmpi determines that "abcz" is greater than "abcdefg" and returns the difference of z and d.

The language (locale) selected by the user at setup time, or by using the control panel, determines which string is greater (or whether the strings are the same). If no language (locale) is selected, Windows performs the comparison by using default values.

For some locales, the lstrcmpi function may be insufficient. If this occurs, use CompareString to ensure proper comparison. For example, in Japan call CompareString with the IGNORE_CASE, IGNORE_KANATYPE, and IGNORE_WIDTH values to achieve the most appropriate non-exact string comparison. The IGNORE_KANATYPE and IGNORE_WIDTH values are ignored in non-Asian locales, so you can set these values for all locales and be guaranteed to have a culturally correct "insensitive" sorting regardless of the locale. Note that specifying these values slows performance, so use them only when necessary.

With a double-byte character set (DBCS) version of Windows, this function can compare two DBCS strings.

The Win32 lstrcmpi function uses a word sort, rather than a string sort. A word sort treats hyphens and apostrophes differently than it treats other symbols that are not alphanumeric, in order to ensure that words such as "coop" and "co-op" stay together within a sorted list. Note that in 16-bit versions of Windows, lstrcmpi uses a string sort. For a detailed discussion of word sorts and string sorts, see the Remarks section of the reference page for the CompareString function .

See Also

, lstrcat, lstrcmp, lstrcpy, lstrlen

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