what are the linux C extensions? discuss in big page in same context as hosted C? Does musl include Linux c extensions?
fuzz testing + C linux has an h3 on static analysis, dynamic analysis and gdb. Maybe this could be its own separate big page along with development stuff? + could be in "More on linux, after IDEs" + or could move/adapt "validating code and compilers"
gnu autoupdate/autoconf?
"..hosted C AND BOOTSTRAPPING ASSEMBLERS AND A C COMPILER"
ldd command. shows what libraries associated with command. owned by glibc
ensure not missing any from gnu/unix: https://en.wikipedia.org/wiki/C_POSIX_library
using backtrace() function from glibc to do stack trace
shared object: .so.n (n is version number in integer. eg v 6.0 through 6.9 would have same interface so could be used in .so.6) static library: .o
difference between GAC (GNU assembly code) and NASM somewhere
printk (print in kernel world, different to printf in user world) module_init() and module_exit() to specify functions to run when module loaded and unloaded
#include <linux/module.h> to use module_init() and module_exit()
#include <linux/init.h> to use __init and __exit
#include <linux/fs.h> to use file_operations structc standard library allows for editing environment variables
mmap and mummap different to heap? used for accessing files and devices + is this standard library or something else?
heap stuff + c sytstem calls used to allocate heap. why? + mmap munmap vs malloc + rather than allocate for each part of the heap, can allocate huge amount and then allocate within by hand. allows domain specific understanding to be reflected. can increase efficiency.
error handling
+ c printing:
linkers. static. dynamic. c exception handling + raise requires signal.h
use of static in c, in unix (applies to other files, not really core c logic) (is is part of library)?
for unix: grab c arguments using main int main (int argc, char **argv)
DNDEBUG can use this flag to remove asserts. used for production <fenv.h> floating point functions for controlling specific work environment?
following 2 are macros for int and float respectively. seem to be environemnt/distro related? <limits.h> <float.h>
<iso646.h> macros so can say "and" instead of &&. here not in c because based on macros <stdnoreturn.h> macros on returning? <stdalign.h> macros for "alignment"???
assembler: assemvly to object file linker: object file to executable eg object has placeholders for how to implement printf. linker gets this from libraries. relocation
use of $(MAKE) in makefiles. up-clean: $(MAKE) down-clean $(MAKE) up
when compile in gcc, specify the example.c file to be compiled too make + installing + configure (get info on system for make process) + make (compile) + make install (copy files to system)
gcc: + -S flag compiles to assembly + -c flag creates object file + -ffreestanding to do that over hosted + -fhosted to force hosted
limits and float on same page? also stdint?
c headers on stuff: + GNU scientific library. GSL. + Basic Linear Algebra Subprograms (BLAS) (is this just cpu?) + openmp (open multiprocessing) (is this cpu header for c?)
outside of standard library is also some linux/posix specific header stuff + fcntl.h + unist.h note, these are not part of c standard library
m4 (macro processor) autoconf automake debugedit libtool
page on linter
making own header file
#include "myhead.h"best practice: splitting up function declearation and function definitions just have declarations in .h make .c file with same name. eg example.h and example.c have definitions in c
#include "example.h" in example.ccan guard against name already existing in .h file
#ifndef MY_HEADER_H
# define MY_HEADER_H
//put your function headers here
#endifDynamic Kernel Module Support (DKMS) + Allows modules with source code outside linux kernel source tree
page on kthreads.h
h3 on changing linux kernel + compiling the kernel + flags + adding/removing modules + pattching code + eBPF (extended berkely packet filter, but not really a network thing. allows programs to run skipping the kernel??)