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Altera_Forum's avatar
Altera_Forum
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21 years ago

A bug in libm.a?

All,

Today, when I build my application without any debugging information, everything is OK. But when I am going to link the .gdb file for debugging, the problem shows up. I got an "undefined error" when linking the .bin file into .gdb file. After checking the problem, I found in the Rules.mak file, it still uses the lib provided by newlib not uclibc, while we are using the libc.a from uclibc.

After changing the LIBM to libm.a provided from uclibc, the problem is solved.

Is it a bug?

<div class='quotetop'>QUOTE </div>

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######################################################## # I use the libm.a provided by uclibc instead of# newlib.# # ######################################################

LIBM := $(LIBCDIR)/lib/libm.a# LIBM := $(shell $(CC) -print-file-name=libm.a)[/b]

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3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Hi,

    We used the newlib&#39;s libm because we found it to be more efficient. What was the specific error message that you got?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Hi, Randy,

    The following is the error information I got. Thanks.

    <div class='quotetop'>QUOTE </div>

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    nios2-elf-ld -T C:/altera/kits/nios2/bin/eclipse/plugins/com.microtronix.nios2linux.application_0.1.0/scripts/elf2flt.ld -o kvm_g.gdb kvm_g.bin

    kvm_g.bin(.text+0x3b298): In function `fmod&#39;:

    /build/nios2/bin/nios2-gnutools/src/newlib/newlib/libm/math/w_fmod.c:97: undefined reference to `__errno&#39;

    kvm_g.bin(.text+0x3b2c8):/build/nios2/bin/nios2-gnutools/src/newlib/newlib/libm/math/w_fmod.c:100: undefined reference to `__errno&#39;

    make[1]: *** [kvm_g.gdb] Error 1[/b]

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Hi neo,

    Yes. It is a problem. You are right to use the libm from uClibc. The libm from newlib is compiled with newlib header files, and should not be used together with uClibc. Thanks for your finding,

    wentao