Comment # 10 on bug 1232536 from Jiri Slaby

(In reply to Petr Vorel from comment #8)
> > on TW (notice there's no "readline" function):
> readelf -Wa /usr/bin/bash |grep -w 'FUNC.* readline'
>    212: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND readline

It is dynamically linked from libreadline. libreadline contains the
implementation:
readelf -Wa /usr/lib64/libreadline.so.8 | grep -w 'FUNC.* readline'
   696: 0000000000027f20   169 FUNC    GLOBAL DEFAULT   15 readline

> > on debian:
> $ readelf -Wa /usr/bin/bash |grep -w 'FUNC.* readline'
>    926: 00000000000cce60   169 FUNC    GLOBAL DEFAULT   15 readline

Apparently, statically linked to libreadline, so bash _contains_ the
implementation.