I am attempting to use the shadow suite password file
locking routines, but only the locking one of them seems to
be in the glibc libraries.  I get the following error
message:

/tmp/cca126091.o: In function `main':
/tmp/cca126091.o(.text+0x3d): undefined reference to
`ulckpdwf'

when I attempt to compile the following program:

#include <stdio.h>
#include <shadow.h>

void main(void) {

        int i;

        i = lckpwdf();
        printf("Press enter to continue.");
        i = getchar();
        printf("Done.\n");
        i = ulckpdwf();
}


Any ideas?