The nix file is besides the point - it gives you a totally hermetic build environment. Not OP, but it’s the only way I know how to get gcc to use a static glibc. All you should pay attention to is that it’s using a static glibc.

$out is a magic variable in nix that means the output of the derivation - the directory that nix moves to its final destination

▲ JoshTriplett 6 months ago | parent | next [-]

> Not OP, but it’s the only way I know how to get gcc to use a static glibc.

    /tmp$ gcc -O3 test.c -o test
    /tmp$ ldd test
     linux-vdso.so.1 (0x00007f3d9fbfe000)
     libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f3d9f9e8000)
     /lib64/ld-linux-x86-64.so.2 (0x00007f3d9fc00000)
    /tmp$ gcc -static -O3 test.c -o test
    /tmp$ ldd test
     not a dynamic executable

▲

fuzztester 6 months ago | parent | next [-]

>> Not OP, but it’s the only way I know how to get gcc to use a static glibc.

> /tmp$ gcc -static -O3 test.c -o test /tmp$ ldd test not a dynamic executable

yes, that last line above means it's a statically linked executable.

yes, i had a doubt about what the GP said, about their nix way being the only way to create a statically linked executable.

but I didn't remember all the details, because it's been a while since I worked with C in depth (moved to Java, Ruby, Python, etc.)(though I did a lot of that earlier, even in pre-Linux years), so I didn't say anything else. thanks, Josh Triplett for clarifying.

but one thing I do remember, is that static linking was the only option in the beginning, at least on Unix, and dynamic linking came only some time later.

when I started working on UNIX and C, there was no dynamic linking at all, IIRC.

https://en.m.wikipedia.org/wiki/Static_library

("dynamic linking" topic in above page links to the below page in Wikipedia: )

https://en.m.wikipedia.org/wiki/Dynamic_linker

▲

3836293648 6 months ago | parent | prev [-]

I thought glibc had some hacks in it to prevent it from working fully when statically linked? Is this just a myth or outdated or only affects C/C++ or what?

	▲	JoshTriplett 6 months ago \| parent [-]
		The issue is that some features of glibc want to dlopen additional libraries, most notably NSS. If you call `gethostbyname`, even a static glibc will try to dlopen NSS libraries based on /etc/nsswitch.conf, and if the dynamic NSS libraries are incompatible with your statically linked glibc, you'll have problems. musl, by contrast, doesn't support NSS at all, only /etc/hosts and DNS servers listed in /etc/resolv.conf, so whether you statically or dynamically link musl, you just won't have any support for (for instance) mDNS, or dynamic users, or local containers, or various other bits of name resolution users may expect to Just Work.

▲ fuzztester 6 months ago | parent | prev | next [-]

thanks.

▲ fuzztester 6 months ago | parent | prev [-]

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