gcc -DLINUX -ansi -I/home/wl/mywork/apue.2e/include -Wall -D_GNU_SOURCE -I/home/wl/mywork/apue.2e/include -L../lib umask.c ../lib/libapue.a -o umask
gcc -DLINUX -ansi -I/home/wl/mywork/apue.2e/include -Wall -D_GNU_SOURCE -I/home/wl/mywork/apue.2e/include -L../lib unlink.c ../lib/libapue.a -o unlink
gcc -DLINUX -ansi -I/home/wl/mywork/apue.2e/include -Wall -D_GNU_SOURCE -I/home/wl/mywork/apue.2e/include -L../lib zap.c ../lib/libapue.a -o zap
编译成功