strcmp.c File Reference

#include <string.h>

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Functions
int	strcmp (const char *s1, const char *s2)
	Compares two null-terminated byte strings lexicographically. More...

Function Documentation

strcmp()

int strcmp	(	const char *	s1,
		const char *	s2
	)

Compares two null-terminated byte strings lexicographically.

Compares two null-terminated byte strings lexicographically.

The behavior is undefined if s1 or s2 are not pointers to null-terminated byte strings.

Parameters

s1	pointers to the null-terminated byte strings to compare
s2	pointers to the null-terminated byte strings to compare

Returns

Negative value if s1 appears before s2 in lexicographical order. Zero if s1 and s2 compare equal, or if n is zero. Positive value if s1 appears after s2 in lexicographical order.

Definition at line 12 of file strcmp.c.

{
    int r = -1;

    if(s1 == s2)
    {
        // short circuit - same string
        return 0;
    }

    // I don't want to panic with a NULL ptr - we'll fall through and fail w/ -1
    if(s1 != NULL && s2 != NULL)
    {
        // iterate through strings until they don't match or s1 ends (null-term)
        for(; *s1 == *s2; ++s1, ++s2)
        {
            if(*s1 == 0)
            {
                r = 0;
                break;
            }
        }

        // handle case where we didn't break early - set return code.
        if(r != 0)
        {
            r = *(const char*)s1 - *(const char*)s2;
        }
    }

    return r;
}

References NULL.

Referenced by strcoll(), wctrans(), and wctype().

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