GCC选项——不使用默认系统库函数及不搜索默认头文件路径

1.序

在某些特殊情况,不需要使用系统自带的库及头文件(比如使用GCC编译实时系统时),那么就需要指定参数,不去搜索默认路径及库文件。

2.命令选项

-nostdinc 不搜索默认路径头文件

-nostdinc
    Do not search the standard system directories for header fles. Only the directories you have specifed with ‘-I’ options (and the directory of the current file,if appropriate) are searched.

类似的选项：

-nostdinc++
Do not search for header fles in the C++-specifc standard directories, but do
still search the other standard directories. (This option is used when building
the C++ library.)

-nostdlib 不使用标准库

Do not use the standard system startup fles or libraries when linking. No
startup fles and only the libraries you specify will be passed to the linker. The
compiler may generate calls to memcmp, memset, memcpy and memmove. These
entries are usually resolved by entries in libc. These entry points should be
supplied through some other mechanism when this option is specifed.
One of the standard libraries bypassed by ‘-nostdlib’ and ‘-nodefaultlibs’
is ‘libgcc.a’, a library of internal subroutines that GCC uses to overcome
shortcomings of particular machines, or special needs for some languages. (See
Section “Interfacing to GCC Output” in GNU Compiler Collection (GCC) Internals, for more discussion of ‘libgcc.a’.) In most cases, you need ‘libgcc.a’
even when you want to avoid other standard libraries. In other words, when you
specify ‘-nostdlib’ or ‘-nodefaultlibs’ you should usually specify ‘-lgcc’ as
well. This ensures that you have no unresolved references to internal GCC
library subroutines. (For example, ‘__main’, used to ensure C++ constructors
will be called; see Section “collect2” in GNU Compiler Collection (GCC)
Internals.)

3.测试

测试可以通过一个简单的例子来查看，进行对比。gcc -v 可以查看。

# gcc -v -o test test.c

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.8/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.3' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-i386 --with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-targets=all --enable-multiarch --disable-werror --with-arch-32=i686 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) 
COLLECT_GCC_OPTIONS='-v' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/cc1 -quiet -v -imultiarch i386-linux-gnu test.c -quiet -dumpbase test.c -mtune=generic -march=i686 -auxbase test -version -fstack-protector -Wformat -Wformat-security -o /tmp/ccSxlviz.s
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/i386-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/i686-linux-gnu/4.8/include
 /usr/local/include
 /usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
 /usr/include/i386-linux-gnu
 /usr/include
End of search list.
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 9dadfc6552e733d9314bd8a1f66914a8
COLLECT_GCC_OPTIONS='-v' '-o' 'test' '-mtune=generic' '-march=i686'
 as -v --32 -o /tmp/ccEhOPIO.o /tmp/ccSxlviz.s
GNU assembler version 2.24 (i686-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.24
COMPILER_PATH=/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../lib/:/lib/i386-linux-gnu/:/lib/../lib/:/usr/lib/i386-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/collect2 --sysroot=/ --build-id --eh-frame-hdr -m elf_i386 --hash-style=gnu --as-needed -dynamic-linker /lib/ld-linux.so.2 -z relro -o test /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crt1.o /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crti.o /usr/lib/gcc/i686-linux-gnu/4.8/crtbegin.o -L/usr/lib/gcc/i686-linux-gnu/4.8 -L/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu -L/usr/lib/gcc/i686-linux-gnu/4.8/../../../../lib -L/lib/i386-linux-gnu -L/lib/../lib -L/usr/lib/i386-linux-gnu -L/usr/lib/../lib -L/usr/lib/gcc/i686-linux-gnu/4.8/../../.. /tmp/ccEhOPIO.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/i686-linux-gnu/4.8/crtend.o /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crtn.o

# gcc -v -nostdlib -o test test.c

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.8/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.3' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-i386 --with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-targets=all --enable-multiarch --disable-werror --with-arch-32=i686 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) 
COLLECT_GCC_OPTIONS='-v' '-nostdlib' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/cc1 -quiet -v -imultiarch i386-linux-gnu test.c -quiet -dumpbase test.c -mtune=generic -march=i686 -auxbase test -version -Wformat -Wformat-security -o /tmp/ccZIvE5J.s
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/i386-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/i686-linux-gnu/4.8/../../../../i686-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/i686-linux-gnu/4.8/include
 /usr/local/include
 /usr/lib/gcc/i686-linux-gnu/4.8/include-fixed
 /usr/include/i386-linux-gnu
 /usr/include
End of search list.
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 9dadfc6552e733d9314bd8a1f66914a8
COLLECT_GCC_OPTIONS='-v' '-nostdlib' '-o' 'test' '-mtune=generic' '-march=i686'
 as -v --32 -o /tmp/ccFQ04Sp.o /tmp/ccZIvE5J.s
GNU assembler version 2.24 (i686-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.24
COMPILER_PATH=/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i686-linux-gnu/4.8/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../../lib/:/lib/i386-linux-gnu/:/lib/../lib/:/usr/lib/i386-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/i686-linux-gnu/4.8/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-nostdlib' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/collect2 --sysroot=/ --build-id --eh-frame-hdr -m elf_i386 --hash-style=gnu --as-needed -dynamic-linker /lib/ld-linux.so.2 -z relro -o test -L/usr/lib/gcc/i686-linux-gnu/4.8 -L/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu -L/usr/lib/gcc/i686-linux-gnu/4.8/../../../../lib -L/lib/i386-linux-gnu -L/lib/../lib -L/usr/lib/i386-linux-gnu -L/usr/lib/../lib -L/usr/lib/gcc/i686-linux-gnu/4.8/../../.. /tmp/ccFQ04Sp.o
/usr/bin/ld: warning: cannot find entry symbol _start; defaulting to 00000000080480d8
/tmp/ccFQ04Sp.o: In function `os_sprintf':
test.c:(.text+0x28): undefined reference to `vsnprintf'
collect2: error: ld returned 1 exit status

# gcc -v -nostdinc -o test test.c

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.8/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.3' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-i386 --with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-targets=all --enable-multiarch --disable-werror --with-arch-32=i686 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) 
COLLECT_GCC_OPTIONS='-v' '-nostdinc' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/cc1 -quiet -nostdinc -v -imultiarch i386-linux-gnu test.c -quiet -dumpbase test.c -mtune=generic -march=i686 -auxbase test -version -fstack-protector -Wformat -Wformat-security -o /tmp/ccuxSCTY.s
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
#include "..." search starts here:
#include <...> search starts here:
End of search list.
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 9dadfc6552e733d9314bd8a1f66914a8
test.c:1:19: error: no include path in which to search for stdio.h
 #include <stdio.h>
                   ^
test.c:2:21: error: no include path in which to search for stdbool.h
 #include <stdbool.h>
                     ^
test.c:3:20: error: no include path in which to search for stdarg.h
 #include <stdarg.h>
                    ^
test.c: In function 'os_sprintf':
test.c:10:2: error: unknown type name 'va_list'
  va_list args;
  ^

# gcc -v -nostdinc -nostdlib -o test test.c

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.8/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.4-2ubuntu1~14.04.3' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-i386 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-i386 --with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-targets=all --enable-multiarch --disable-werror --with-arch-32=i686 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) 
COLLECT_GCC_OPTIONS='-v' '-nostdinc' '-nostdlib' '-o' 'test' '-mtune=generic' '-march=i686'
 /usr/lib/gcc/i686-linux-gnu/4.8/cc1 -quiet -nostdinc -v -imultiarch i386-linux-gnu test.c -quiet -dumpbase test.c -mtune=generic -march=i686 -auxbase test -version -Wformat -Wformat-security -o /tmp/ccfKqwKi.s
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
#include "..." search starts here:
#include <...> search starts here:
End of search list.
GNU C (Ubuntu 4.8.4-2ubuntu1~14.04.3) version 4.8.4 (i686-linux-gnu)
        compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version 3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 9dadfc6552e733d9314bd8a1f66914a8
test.c:1:19: error: no include path in which to search for stdio.h
 #include <stdio.h>
                   ^
test.c:2:21: error: no include path in which to search for stdbool.h
 #include <stdbool.h>
                     ^
test.c:3:20: error: no include path in which to search for stdarg.h
 #include <stdarg.h>
                    ^
test.c: In function 'os_sprintf':
test.c:10:2: error: unknown type name 'va_list'
  va_list args;
  ^

4.总结

对于这些命令而言,需要对GCC手册比较熟悉,熟悉这些选项对个人成长而言是有非常大的帮助的。
比如写makefile,写shell脚本的时候,可能都需要用到类似的选项。

I.拓展

readelf -d TEST_ELF 可以查看TEST_ELF所依赖的库信息.

 如： readelf -d  `which lua`
 Dynamic section at offset 0x35efc contains 27 entries:
  Tag        Type                         Name/Value
 0x00000001 (NEEDED)                     Shared library: [libm.so.6]
 0x00000001 (NEEDED)                     Shared library: [libdl.so.2]
 0x00000001 (NEEDED)                     Shared library: [libreadline.so.6]
 0x00000001 (NEEDED)                     Shared library: [libc.so.6]
 0x0000000c (INIT)                       0x804a8e8
 0x0000000d (FINI)                       0x806f0a4
 0x00000019 (INIT_ARRAY)                 0x807eef0
 0x0000001b (INIT_ARRAYSZ)               4 (bytes)
 0x0000001a (FINI_ARRAY)                 0x807eef4
 0x0000001c (FINI_ARRAYSZ)               4 (bytes)
 0x6ffffef5 (GNU_HASH)                   0x80481ac
 0x00000005 (STRTAB)                     0x8049704
 0x00000006 (SYMTAB)                     0x80486d4
 0x0000000a (STRSZ)                      3070 (bytes)
 0x0000000b (SYMENT)                     16 (bytes)
 0x00000015 (DEBUG)                      0x0
 0x00000003 (PLTGOT)                     0x807f000
 0x00000002 (PLTRELSZ)                   736 (bytes)
 0x00000014 (PLTREL)                     REL
 0x00000017 (JMPREL)                     0x804a608
 0x00000011 (REL)                        0x804a5e8
 0x00000012 (RELSZ)                      32 (bytes)
 0x00000013 (RELENT)                     8 (bytes)
 0x6ffffffe (VERNEED)                    0x804a508
 0x6fffffff (VERNEEDNUM)                 3
 0x6ffffff0 (VERSYM)                     0x804a302
 0x00000000 (NULL)                       0x0

gcc -print-file-name=XXX.so 可以查看XXX.so库文件的路径.

如：gcc -print-file-name=libreadline.so.6
/lib/i386-linux-gnu/libreadline.so.6

组合命令：readelf -d `gcc -print-file-name=libreadline.so.6`

Dynamic section at offset 0x38b88 contains 26 entries:
  Tag        Type                         Name/Value
 0x00000001 (NEEDED)                     Shared library: [libtinfo.so.5]
 0x00000001 (NEEDED)                     Shared library: [libc.so.6]
 0x0000000e (SONAME)                     Library soname: [libreadline.so.6]
 0x0000000c (INIT)                       0xb0fc
 0x0000000d (FINI)                       0x2e484
 0x00000019 (INIT_ARRAY)                 0x39278
 0x0000001b (INIT_ARRAYSZ)               4 (bytes)
 0x0000001a (FINI_ARRAY)                 0x3927c
 0x0000001c (FINI_ARRAYSZ)               4 (bytes)
 0x6ffffef5 (GNU_HASH)                   0x138
 0x00000005 (STRTAB)                     0x45ec
 0x00000006 (SYMTAB)                     0x15ac
 0x0000000a (STRSZ)                      13381 (bytes)
 0x0000000b (SYMENT)                     16 (bytes)
 0x00000003 (PLTGOT)                     0x3a000
 0x00000002 (PLTRELSZ)                   848 (bytes)
 0x00000014 (PLTREL)                     REL
 0x00000017 (JMPREL)                     0xadac
 0x00000011 (REL)                        0x80dc
 0x00000012 (RELSZ)                      11472 (bytes)
 0x00000013 (RELENT)                     8 (bytes)
 0x6ffffffe (VERNEED)                    0x803c
 0x6fffffff (VERNEEDNUM)                 1
 0x6ffffff0 (VERSYM)                     0x7a32
 0x6ffffffa (RELCOUNT)                   1172
 0x00000000 (NULL)                       0x0