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In article <2heefv$btl@agate.berkeley.edu> sternber@haas.berkeley.edu (Theodore Sternberg) writes:
>What does...
>test.c:11: warning: passing arg 5 of `bsearch' from incompatible pointer type
>...mean?  Here's the code (which, incidentally, raises no problems
>with ULTRIX's cc)...
>
>#include <stdlib.h>
>#include <string.h>
>
>int charcompare( char, char );
>
>main() {
>  char str1[10], *str2;
>  strcpy( str1, "abcdefghi" );
>
>  str2 = bsearch( (char *)'e', str1, 9, 1, charcompare );
>}
>/*---------------------------------*/
>
>int charcompare( char ch1, char ch2 ) {
>   return ch1 - ch2;
>}

Well, the 5th argument in your call to bsearch is charcompare, which is
a [pointer to a] function of two arguments (a char and a char) that
returns an int.  The SunOS 4.1.3 man page for bsearch says only that
"the comparison function ... is called with two arguments that point to
the elements being compared."  The "POSIX Programmer's Guide" by Donald
Lewine (O'Reilly & Associates) gives this declaration:

int (*compar) (const void *, const void *);

Your charcompar function is incompatible with the declared type of
bsearch's 5th argument, because its argument types are not pointers; you
need to change

	int charcompare( char, char );

to

	int charcompare(const char *, const char *);

and

	int charcompare (char ch1, char ch2)
	{
	   return ch1 - ch2;
	}

to

	int charcompare (const char *ch1, const char *ch2)
	{
	   return *ch1 - *ch2;
	}
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