warning: statement has no effect [-Wunused-value]

While working on a library I used the 'strcpy' function within a method.

strcmp(pBuff, "Unknown");

When it compiles I get the warning message:
warning: statement has no effect [-Wunused-value]

I have no idea how a function call to a standard library function can have no effect.

I also tried the statement:

strcmp_P(pBuff, (PGM_P) F("Unknown"));

This compiles without error but does not work (i.e. buffer remains unchanged).

That's strcmp you have there, not strcpy... Compare two strings and throw away the result...?

If you want to copy a string, you probably shouldnt use strcmp() to do it.

DAH