在 centos 上找不到 libl 9 - /usr/bin/ld: 找不到 -ll

Question

Brand new install of centos 9. (mostly minimal)

I did a find and there is no libl.so on my machine.

sudo yum install bison Last metadata expiration check: 1:52:29 ago on Wed 23 Feb 2022 01:25:31 PM EST. Package bison-3.7.4-5.el9.x86_64 is already installed.

sudo yum install flex Last metadata expiration check: 1:52:25 ago on Wed 23 Feb 2022 01:25:31 PM EST. Package flex-2.6.4-9.el9.x86_64 is already installed.

sudo yum install flex-devel Last metadata expiration check: 1:52:35 ago on Wed 23 Feb 2022 01:25:31 PM EST. No match for argument: flex-devel

I tried installing sudo yum groupinstall 'Development Tools'

nothing works, any ideas?

Answer 1

As you pointed out in the question - flex-devel is not found.

It's in the PowerTools repo.

The 'official' way to enable the repo is to use the yum config-manager command line:

yum config-manager --set-enabled powertools

This may give an error about being missing the config-manager command:

No such command: config-manager

If this happens, then you can install the dnf-plugins-core package:

yum install -y dnf-plugins-core

and then enable the powertools repo, and then you should be able to yum install flex-devel , which provides:

$ rpmquery --list flex-devel
/usr/lib64/libfl.a
/usr/lib64/libfl_pic.a
/usr/lib64/libl.a
/usr/share/doc/flex
/usr/share/licenses/flex-devel
/usr/share/licenses/flex-devel/COPYING

Answer 2

The static libraries ( libfl.a and libl.a ), which is what were provided before in the package flex-devel , have been moved to the package libfl-static . I don't know if RedHat ever provided shared objects; there's a note in the libfl-static ChangeLog that seems to be saying that there is a new package called libfl2 with shared objects, but I don't see it in the package repo. Anyway, static libraries should be fine. There's hardly anything there.

If you're using libl , that means that:

• you aren't using %option noyywrap , which will remove the call to yywrap (and if you're using the version of yywrap in libl , then you don't need it to call the function, since that version unconditionally returns 1), and/or
• you haven't provided your own main function.

I strongly recommend including the following options in all flex files, unless you have a clear need for the suppressed features:

%option noinput nounput noyywrap nodefault

The main function in libl is also trivial. It can be replaced with:

int main(void) {
  while (yylex() != 0) { }
  return 0;
}