Linking to multiple libraries, one of which includes a set of system calls

Question

So this is the scenario I'm looking at:

I have 3 libraries - A, B and C.

• Library A implements the foo() function and provides it as an API.
• The foo() function calls the POSIX write() call to write some data.
• Library B writes the shell to the write() call of glibc using the linker -wrap option.
• Library C refers to A and B.

Any call to write() that the C make library will be intercepted by the B library shell. But, my question is, if the C library calls foo() , the write() call inside foo () will be intercepted by B?

Answer 1

If A is associated with -wrap=write , foo will invoke the shell. If not, it will not.

The same can be said for write calls in C There is no difference between A and C regarding the write call.