找不到非标准 header 包括

Question

I am not using standard gcc headers. I am building with -nostdlib and -nostdinc options. These options force the compiler to not use standard headers.

I am using newlib for my custom kernel development. newlib contains headers and other libs.

https://stackoverflow.com/a/30792552/13014162

The error when I type make :

lib/builtins/lib_int.h:29:12: fatal error: 'stdint.h' file not found
#  include <stdint.h>
           ^
1 error generated.
Makefile:90: recipe for target 'lib/builtins/kern_lib.o' failed

So, when building the compiler should pick up the stdint.h from newlib (instead from standard header). Why is it not picking it?

This project has already been built by others previously. So there is something in my setup that is wrong. I believe that include paths and other things are correctly setup because others are able to build it.

Can someone point to me specifically how to USE newlib . I checked that newlib has stdint.h inside it.

Answer 1

From the newlib README.txt file:

To compile a program against shared newlib:

 gcc -nostdlib $(target_install_dir)/lib/crt0.o progname.c -I $(target_install_dir)/include -L $(target_install_dir)/lib -lc -lm -lgcc

To run the program, make sure that $(target_install_dir)/lib is listed in the LD_LIBRARY_PATH environment variable.

To create a static binary linked against newlib, do the following:

 gcc -nostdlib -static $(target_install_dir)/lib/crt0.o progname.c -I $(target_install_dir)/include -L $(target_install_dir)/lib -lc -lm

The above is written in Makefile format, with progname.c being the name of the source file to compile, and $(target_install_dir) being the directory where newlib was installed into. If you are unsure, you can run find ~/ /usr /lib* -name crt0.o ; newlib should be installed in two directories above one of the outputs. If that command doesn't output anything, you haven't installed newlib yet.

Personally, I'd try with something like the following Makefile:

INCNEWLIB := /usr/include/newlib
LIBNEWLIB := /usr/lib/arm-none-eabi/newlib
CRT0      := $(LIBNEWLIB)/crt0.o
CC        := /usr/bin/arm-none-eabi-gcc
CFLAGS    := -Wall -Wextra -O2
LDFLAGS   :=

%.o: %.c
    $(CC) $(CFLAGS) -nostdlib -I $(INCNEWLIB) $^ -c -o $@

# For dynamically linked binary executables:
dynamic-bin: your.o object.o files.o here.o
    $(CC) $(CFLAGS) -nostdlib $(CRT0) $^ -L $(LIBNEWLIB) -lc -lgcc $(LDFLAGS) -o $@

# For statically linked binary executables:
static-bin: your.o object.o files.o here.o
    $(CC) $(CFLAGS) -static -nostdlib $(CRT0) $^ -L $(LIBNEWLIB) -lc $(LDFLAGS) -o $@

Note that this forum eats tabs, and Makefiles need to be indented with tabs, so if you copy-paste the above, fix the indentation using eg sed -e 's|^ *|\t|' -i Makefilesed -e 's|^ *|\t|' -i Makefile .

The above paths are for Debian/Ubuntu/Mint ARM newlib, edit them to match your system and personal preferences.

You can override any of the variables at the command line. For example, make CRT0=/usr/lib/arm-none-eabi/newlib/thumb/v7e-m/fpv5/hard/crt0.o uses a different startup routines for the binary executable (v7e-m hard-fpv5).