Bash-编译可加载的睡眠

Question

I am trying to compile the sleep loadable that is included in the bash src tarball.

I have tried running the commands listed in post #7 of the following thread,

https://bbs.archlinux.org/viewtopic.php?pid=1366887#p1366887

but I encounter errors when compiling the sleep command.

This is the output I receive when I run make sleep :

System:~/bash-4.0/examples/loadables root# make sleep
gcc -fno-common -DHAVE_CONFIG_H -DSHELL -DMACOSX -g -O2 -I. -I.. -I../.. -I../../lib -I../../builtins -I../../include -I/var/root/bash-4.0 -I/var/root/bash-4.0/lib -I/var/root/bash-4.0/builtins -I../../lib/intl -I/var/root/bash-4.0/lib/intl -c -o sleep.o sleep.c
gcc -dynamic   -o sleep sleep.o
Undefined symbols:
  "_main", referenced from:
      __start in crt1.10.5.o
  "_fsleep", referenced from:
      _sleep_builtin in sleep.o
  "_builtin_usage", referenced from:
      _sleep_builtin in sleep.o
  "_builtin_error", referenced from:
      _sleep_builtin in sleep.o
  "_uconvert", referenced from:
      _sleep_builtin in sleep.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [sleep] Error 1

Does anyone know how to get the bash sleep loadable to compile?

Thanks in advance.

Update:

The source code was dowloaded from http://ftp.gnu.org/gnu/bash/bash-4.0.tar.gz . It has not been modified.

Why do I want to use the sleep loadable?

I have a couple programs that that wait for something to happen, then execute some code, and then wait again. I use the external sleep program to keep them from hogging processor time while looping. I wanted to use the sleep loadable to avoid creating the external sleep process. I have tried using the read command, but that won't work when I run my bash scripts as launchdaemons because there is no terminal. I have also tried using this read command solution ( https://unix.stackexchange.com/questions/68236/#68269 ), but bash only looped twice before freezing.

My goal is to figure out some way to be able to sleep in bash without using an external program.

Answer 1

First we would need to know where you got the source code from and exactly what you have done with it. iOS is based on BSD, not Linux, so archlinux instructions for compiling might not be that relevant. There is also the problem of iOS on the iPhone not actually being a full OS, but a sightly cutdown version.

Also, telling us what is the reason behind wanting sleep, we could possibly offer an alternative. For example if you have read, this should work (is sleep for 5.5 seconds): read -t 5.5 -N 0.

Some also use ping to non-existent IP with a X seconds timeout.