Compiling using arm-none-eabi-gcc and linking library liba.a error

Question

I am compiling a hello world program in C on a 64-bit Linux machine. I am using a GCC ARM embedded toolchain to cross compile my program on a FOX G20 V board with an ATMEL AT91SAM9G20 processor.

On the first take, I had a few errors when compiling because the program didn't recognize the printf, return etc. functions (the standard C functions). So I decided to make the link between the functions, which I believe are defined in the libc.a library (correct me if I'm wrong), by doing arm-none-eabi-gcc -o hello hello.c libc.a but the outcome still results in errors:

libc.a(lib_a-exit.o): In function `exit':
exit.c:(.text.exit+0x16): undefined reference to `_exit'
libc.a(lib_a-sbrkr.o): In function `_sbrk_r':
sbrkr.c:(.text._sbrk_r+0xc): undefined reference to `_sbrk'
libc.a(lib_a-writer.o): In function `_write_r':
writer.c:(.text._write_r+0x10): undefined reference to `_write'
libc.a(lib_a-closer.o): In function `_close_r':
closer.c:(.text._close_r+0xc): undefined reference to `_close'
libc.a(lib_a-fstatr.o): In function `_fstat_r':
fstatr.c:(.text._fstat_r+0xe): undefined reference to `_fstat'
libc.a(lib_a-isattyr.o): In function `_isatty_r':
isattyr.c:(.text._isatty_r+0xc): undefined reference to `_isatty'
libc.a(lib_a-lseekr.o): In function `_lseek_r':
lseekr.c:(.text._lseek_r+0x10): undefined reference to `_lseek'
libc.a(lib_a-readr.o): In function `_read_r':
readr.c:(.text._read_r+0x10): undefined reference to `_read'
collect2: error: ld returned 1 exit status

I'm really unsure as to why the program still does not recognize the standard functions even though I've linked the library to the application. If anyone has a reason as to why, or a solution as to how I can fix this problem, I would be very grateful.

UPDATE

I've downloaded the glibc library from here. I've compiled and created a static library from the syscalls.c library that I found in newlib-2.1.0/libgloss/arm and when I link the library to my application code, I still get the same error.

Exactly what GCC ARM embedded toolchain are you using? It looks like the undefined references are functions that you are (or someone is) expected to write to integrate the libc.a library to the specific platform. — Michael Burr
@MichaelBurr It's the pre-built 32-bit version of Linero GCC. So there is something that I would have to add to the libc.a library? What could that be if so? — Adam

Adam Adam · Accepted Answer · 2014-04-16T08:28:44

Try executing this:

arm-none-eabi-gcc --specs=rdimon.specs -lgcc -lc -lm -lrdimon -o hello hello.c

Your toolkit seems to provide the librdimon.a, a library which provides the basic standard C functions.

Compiling using arm-none-eabi-gcc and linking library liba.a error

2 Answers