PG_CFLAGS rpath Passthrough Issue

On Fri, 2025-03-14 at 12:58 -0400, David E. Wheeler wrote:

I'm trying to compile an extension with PG_CFLAGS1[1]:

```sh
make PG_CFLAGS='-Wl,-rpath,$ORIGIN'
```

This works, but for some reason the rpath value is truncated:

```console
# chrpath -l src/semver.so
src/semver.so: RUNPATH=RIGIN
```

Do I need to do something different to include the missing characters `$O`? Or is there an issue with the quoting of these variables in PGXS?

It is a quoting issue.

Trial and error showed my that the following works:

make CFLAGS='-Wl,-rpath,\$$ORIGIN'

... at least when I run it on the shell. Putting it into an RPM spec file
might require more escaping, no idea.

Yours,
Laurenz Albe

On Mar 14, 2025, at 17:13, Laurenz Albe <laurenz.albe@cybertec.at> wrote:

It is a quoting issue.

Trial and error showed my that the following works:

make CFLAGS='-Wl,-rpath,\$$ORIGIN'

... at least when I run it on the shell. Putting it into an RPM spec file
might require more escaping, no idea.

Confirmed, this works, thank you.

But, just. WAT. 30 years in this business and shell string escaping continues to elude me. I tried lots of different combinations of escaping, but this weird double-$ never occurred to me.

Best,

David

On 2025-Mar-14, David E. Wheeler wrote:

But, just. WAT. 30 years in this business and shell string escaping
continues to elude me. I tried lots of different combinations of
escaping, but this weird double-$ never occurred to me.

It's make. From its info manual:

6.1 Basics of Variable References

To substitute a variable’s value, write a dollar sign followed by the name
of the variable in parentheses or braces: either ‘$(foo)’ or ‘${foo}’ is a
valid reference to the variable foo. This special significance of
‘$’ is why you must write ‘$$’ to have the effect of a single dollar sign in
a file name or recipe.

I'm surprised that you don't need \$\$ though. I wonder if
make CFLAGS='-Wl,-rpath,$$ORIGIN'
isn't enough actually?

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
"Learn about compilers. Then everything looks like either a compiler or
a database, and now you have two problems but one of them is fun."
https://twitter.com/thingskatedid/status/1456027786158776329

On Mar 15, 2025, at 07:58, Álvaro Herrera <alvherre@alvh.no-ip.org> wrote:

It's make. From its info manual:

Oh, that explains it. It hadn’t occurred to me that make could eval strings passed to it like that, but of course it does.

I'm surprised that you don't need \$\$ though. I wonder if
make CFLAGS='-Wl,-rpath,$$ORIGIN'
isn't enough actually?

Oddly, no:

# make CFLAGS='-Wl,-rpath,$$ORIGIN'
# chrpath src/semver.so
src/semver.so: RUNPATH=

Gotta have the backslash.

Best,

David