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我需要在我的 Debian 服务器上安装一个 Ruby gem。这会失败并显示一条错误消息，这对我作为非 ruby​​ 程序员来说不是很有帮助。你能帮我诊断一下问题吗？缺少哪些“必要的库和/或标头”？

root ~ # gem install schleuder
Building native extensions.  This could take a while...
ERROR:  Error installing schleuder:
    ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb
checking for magic_open() in -lmagic... no
*** ERROR: missing required library to compile this module
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/usr/bin/ruby1.8
    --with-magic-dir
    --without-magic-dir
    --with-magic-include
    --without-magic-include=${magic-dir}/include
    --with-magic-lib
    --without-magic-lib=${magic-dir}/lib
    --with-magiclib
    --without-magiclib


Gem files will remain installed in /var/lib/gems/1.8/gems/ruby-filemagic-0.4.2 for inspection.
Results logged to /var/lib/gems/1.8/gems/ruby-filemagic-0.4.2/ext/gem_make.out

日志文件（假设这是正确的）说：

root ~ # cat /var/lib/gems/1.8/gems/ruby-filemagic-0.4.2/ext/mkmf.log
have_library: checking for magic_open() in -lmagic... -------------------- no

"gcc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I.    -fno-strict-aliasing -g -g -O2  -fPIC   conftest.c  -L. -L/usr/lib -L.  -rdynamic -Wl,-export-dynamic     -lruby1.8-static -lmagic  -lpthread -lrt -ldl -lcrypt -lm   -lc"
conftest.c: In function ‘t’:
conftest.c:3: error: ‘magic_open’ undeclared (first use in this function)
conftest.c:3: error: (Each undeclared identifier is reported only once
conftest.c:3: error: for each function it appears in.)
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { void ((*volatile p)()); p = (void ((*)()))magic_open; return 0; }
/* end */

"gcc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I.    -fno-strict-aliasing -g -g -O2  -fPIC   conftest.c  -L. -L/usr/lib -L.  -rdynamic -Wl,-export-dynamic     -lruby1.8-static -lmagic  -lpthread -lrt -ldl -lcrypt -lm   -lc"
/usr/bin/ld: cannot find -lmagic
collect2: ld returned 1 exit status
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { magic_open(); return 0; }
/* end */

--------------------
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1 回答 1

2

一些 Ruby gem 带有“本地扩展”，这意味着它们不是完全用 Ruby 编写的，而是包含与一些用 C 编写的外部库的绑定。这通常是出于性能原因，或者是为了使用完善的库而不是重新发明轮子。

在您的情况下，它无法编译本机扩展，因为缺少头文件。您可能需要安装libmagic-devDebian 软件包。就像是

sudo apt-get install libmagic-dev

会做的伎俩，这取决于你的包管理器！

于 2012-12-03T12:13:43.247 回答