What's the structure of glibc's source code

Question

I tried to look for a specific function, e.g fstatfs, but I found the following code, it does almost nothing, I checked __set_errno macro, it's merely setting error number. ``` int __fstatfs (int fd, struct statfs *buf) { __set_errno (ENOSYS); return -1; } ``` So a set of core library are implemented in ASM, but how is that working, if so why does these weak function even exist ?

Accepted Answer

I guess that the call is OS-dependent, so what you're seeing is just a stub. There seems to be some kind of alias in io/sys/statfs.h, and a candidate for the Linux implementation is in sysdeps/unix/sysv/linux/fstatfs64.c file.

What's the structure of glibc's source code

Solution

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