How does C code call assembly code (e.g. optimized strlen)?

How does C code call assembly code (e.g. optimized strlen)?

c unix assembly

unix

The structure of Deflate compressed block

unix assembly bit-manipulation gzip deflate

unix

Why doesn't Linux follow Unix syscall conventions?

c linux unix assembly x86

unix

UNIX V6 processes swap time

c unix assembly pdp-11

unix

Is assembler portable between Linux distros?

linux unix assembly portability

unix

Assembly code . = 60^. in low.s file of UNIX V6 source code

unix assembly

unix

objdump adjust vma offset in gnu Utilities

linux unix assembly gnu objdump

unix

Using NASM and TCP Sockets

sockets unix assembly x86 nasm

unix

gcc generates unnecessary (?) instructions

c unix gcc assembly

unix

intel 8080: Am I missing something in this code?

unix assembly cpu-registers intel-8080

unix

Issue with strchr() function implementation

unix assembly x86-64

unix