Byte-to-binary conversion function

My implementation of a binary-to-bits converting function:

#include 
#include 

unsigned char *return_byte (unsigned char source)
{
    static unsigned char byte[CHAR_BIT];
    unsigned char *p = byte, i;

    for(i = 0; i  0);

    return p;
}

int main(void)
{
    unsigned char val = 200;

    printf("Value:\t%i\nBinary:\t%s", val, return_byte(val));

    return 0;
}

Output:

Value: 200
Binary: 00010011


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return_byte doesn't tell much what the function is intended to do. btoa would be more in line with C naming convention (akin to itoa)

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A p variable is pretty much useless. Consider

static unsigned char byte[CHAR_BIT];
unsigned char i;

for(i = 0; i  0);

return byte;

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Using an unsigned char for indexing is questionable. In any case it doesn't buy you much against a native int.

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A boolean expression as + operand may raise some eyebrows (true is guaranteed to be a non-zero in an arithmetic context, but it is not guaranteed to be 1). I recommend to force an arithmetic value by right-shifting source instead of left-shifting the mask:

for(i = 0; i >= 1;
}

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You do not null-terminate the resulting string. The fact that your test succeeded is a sheer (un)luck.

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You probably know that returning static makes the code non-reentrant and thread-unsafe. You may want to let client provide a space for a resulting string.

StackExchange Code Review Q#82303, answer score: 3