我正在使用Eclipse为 ARM 处理器交叉编译一个 g++ 项目。我在 Windows 环境中使用 yagarto 工具链。我对 C 项目没有任何问题，但是对于 C++，我不断收到错误：
libc.a(lib_a-abort.o): In function `abort':
abort.c:63: undefined reference to `_exit'
libc.a(lib_a-sbrkr.o): In function `_sbrk_r':
sbrkr.c:58 undefined reference to `_sbrk'
libc.a(lib_a-signalr.o): In function `_kill_r':
signalr.c:61: undefined reference to `_kill'
也：
undefined reference to `_getpid'
undefined reference to `_write'
undefined reference to `_close'
undefined reference to `_fstat'
undefined reference to `_isatty'
undefined reference to `_lseek'
undefined reference to `_read'
环顾四周，我似乎遇到了链接器问题。我试图添加链接器 flash.ld。它来自 Atmel Studio 的 ARM 开发套件的 GCC 示例。这没有帮助。某处是否有用于 g++ 的链接器？我还有其他问题吗？
这是我的构建选项：
make all
Building target: Foo
Invoking: Cross G++ Linker
arm-none-eabi-g++ -nostartfiles -T C:/Users/kempsa/eclipse_workspace/Foo/flash.ld -o"Foo" ./HALTimer1.o ./Main.o
我有源文件 Main.cpp、HALTimer1.cpp 和头文件 Haltimer.h。主文件只包含头文件。头文件只定义了一个带有一个变量的 HALTimer 类。我不相信这些会影响错误。我相信这个错误完全是因为在没有正确链接器文件的情况下构建了一个 g++ 项目。
这是链接器文件的内容：
/**
* \file
*
* \brief Flash Linker script for SAM.
*
* Copyright (c) 2011-2012 Atmel Corporation. All rights reserved.
*
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
OUTPUT_ARCH(arm)
SEARCH_DIR(.)
/* Memory Spaces Definitions */
MEMORY
{
rom (rx) : ORIGIN = 0x00400000, LENGTH = 0x00040000 /* flash has two banks, one bank = 256K */
ram (rwx) : ORIGIN = 0x20000000, LENGTH = 0x00010000 /* sram, 64K */
}
/* The stack size used by the application. NOTE: you need to adjust */
__stack_size__ = DEFINED(__stack_size__) ? __stack_size__ : 0x2000;
/* Section Definitions */
SECTIONS
{
.text :
{
. = ALIGN(4);
_sfixed = .;
KEEP(*(.vectors .vectors.*))
*(.text .text.* .gnu.linkonce.t.*)
*(.glue_7t) *(.glue_7)
*(.rodata .rodata* .gnu.linkonce.r.*)
*(.ARM.extab* .gnu.linkonce.armextab.*)
/* Support C constructors, and C destructors in both user code
and the C library. This also provides support for C++ code. */
. = ALIGN(4);
KEEP(*(.init))
. = ALIGN(4);
__preinit_array_start = .;
KEEP (*(.preinit_array))
__preinit_array_end = .;
. = ALIGN(4);
__init_array_start = .;
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array))
__init_array_end = .;
. = ALIGN(0x4);
KEEP (*crtbegin.o(.ctors))
KEEP (*(EXCLUDE_FILE (*crtend.o) .ctors))
KEEP (*(SORT(.ctors.*)))
KEEP (*crtend.o(.ctors))
. = ALIGN(4);
KEEP(*(.fini))
. = ALIGN(4);
__fini_array_start = .;
KEEP (*(.fini_array))
KEEP (*(SORT(.fini_array.*)))
__fini_array_end = .;
KEEP (*crtbegin.o(.dtors))
KEEP (*(EXCLUDE_FILE (*crtend.o) .dtors))
KEEP (*(SORT(.dtors.*)))
KEEP (*crtend.o(.dtors))
. = ALIGN(4);
_efixed = .; /* End of text section */
} > rom
/* .ARM.exidx is sorted, so has to go in its own output section. */
PROVIDE_HIDDEN (__exidx_start = .);
.ARM.exidx :
{
*(.ARM.exidx* .gnu.linkonce.armexidx.*)
} > rom
PROVIDE_HIDDEN (__exidx_end = .);
. = ALIGN(4);
_etext = .;
.relocate : AT (_etext)
{
. = ALIGN(4);
_srelocate = .;
*(.ramfunc .ramfunc.*);
*(.data .data.*);
. = ALIGN(4);
_erelocate = .;
} > ram
/* .bss section which is used for uninitialized data */
.bss (NOLOAD) :
{
. = ALIGN(4);
_sbss = . ;
_szero = .;
*(.bss .bss.*)
*(COMMON)
. = ALIGN(4);
_ebss = . ;
_ezero = .;
} > ram
/* stack section */
.stack (NOLOAD):
{
. = ALIGN(8);
_sstack = .;
. = . + __stack_size__;
. = ALIGN(8);
_estack = .;
} > ram
. = ALIGN(4);
_end = . ;
}
完整的编译器输出：
Building target: Foo
Invoking: Cross G++ Linker
arm-none-eabi-g++ -nostartfiles -T C:/Users/kempsa/eclipse_workspace/Foo/flash.ld -o"Foo" ./HALTimer.o ./Main.o
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-abort.o): In function `abort':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\stdlib/../../../../../newlib-1.20.0/newlib/libc/stdlib/abort.c:63: undefined reference to `_exit'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-sbrkr.o): In function `_sbrk_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/sbrkr.c:58: undefined reference to `_sbrk'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-signalr.o): In function `_kill_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/signalr.c:61: undefined reference to `_kill'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-signalr.o): In function `_getpid_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/signalr.c:96: undefined reference to `_getpid'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-writer.o): In function `_write_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/writer.c:58: undefined reference to `_write'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-closer.o): In function `_close_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/closer.c:53: undefined reference to `_close'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-fstatr.o): In function `_fstat_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/fstatr.c:62: undefined reference to `_fstat'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-isattyr.o): In function `_isatty_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/isattyr.c:58: undefined reference to `_isatty'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-lseekr.o): In function `_lseek_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/lseekr.c:58: undefined reference to `_lseek'
c:/yagarto/bin/../lib/gcc/arm-none-eabi/4.7.2/../../../../arm-none-eabi/lib\libc.a(lib_a-readr.o): In function `_read_r':
C:\msys\1.0\home\yagarto\newlib-build\arm-none-eabi\newlib\libc\reent/../../../../../newlib-1.20.0/newlib/libc/reent/readr.c:58: undefined reference to `_read'
collect2.exe: error: ld returned 1 exit status
make: *** [Foo] Error 1