c - 如何使用静态 libcurl 编译程序？

Question

有如下代码:

#include <stdio.h>
#include <curl/curl.h>

int main(void){
  CURL *curl;
  CURLcode res;

  curl = curl_easy_init();

  if(curl == NULL)
    return 0;

  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/getAccessAttributes?id=1");

  res = curl_easy_perform(curl);

  if(res != CURLE_OK) {
    fprintf(stderr, "Error: %s\n", curl_easy_strerror(res));
    return 0;
  }

  curl_easy_cleanup(curl);
  return 0;
}

如果你从动态链接库中收集它一切正常:

gcc test.c -lcurl -o test

现在我想提出一个静态程序:

gcc test.c /tmp/curl/lib/libcurl.a -static -lcurl -lssl -lcrypto -ldl -lm -lz -DCURL_STATICLIB -I/tmp/curl/include -o test

他犯了错误:

/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/libcrypto.a(dso_dlfcn.o): In function dlfcn_globallookup':
(.text+0x11): warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/tmp/curl/lib/libcurl.a(libcurl_la-netrc.o): In functionCurl_parsenetrc': netrc.c:(.text+0x3c8): warning: Using 'getpwuid_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking /tmp/curl/lib/libcurl.a(libcurl_la-curl_addrinfo.o): In function `Curl_getaddrinfo_ex': curl_addrinfo.c:(.text+0x60): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking

该程序仅在您指定主机 IP 地址而不是 example.com 时才有效。否则程序无法解析域名:

$ ./test
Error: Couldn't resolve host name

如何解决名称解析问题？谢谢!

附言静态libcurl我收集了如下方法:

wget http://curl.haxx.se/download/curl-7.44.0.tar.lzma
tar xf curl-7.44.0.tar.lzma
cd curl-7.44.0
./configure --disable-shared --enable-static --prefix=/tmp/curl --disable-ldap --disable-sspi --without-librtmp --disable-ftp --disable-file --disable-dict --disable-telnet --disable-tftp --disable-rtsp --disable-pop3 --disable-imap --disable-smtp --disable-gopher --disable-smb --without-libidn
make && make install

Answer 1

这是动态 libcurl 的样子。

$ ldd test
    linux-vdso.so.1 (0x00007ffcca3aa000)
    libcurl.so.4 => /usr/lib64/libcurl.so.4 (0x00007f5536ed6000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f5536b3e000)
    libssl.so.1.0.0 => /usr/lib64/libssl.so.1.0.0 (0x00007f55368d3000)
    libcrypto.so.1.0.0 => /usr/lib64/libcrypto.so.1.0.0 (0x00007f5536503000)
    libz.so.1 => /lib64/libz.so.1 (0x00007f55362ed000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f5537138000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f55360e9000)

如果只想静态链接 curl，请不要使用 -static。只需将 libcurl.a 添加为目标文件之一或使用 -lcurl，您无需指定它两次。之后

gcc test.c curl-7.44.0/lib/.libs/libcurl.a -lssl -lcrypto -ldl -lm -lz -DCURL_STATICLIB -o test

你会得到

$ ldd test
    linux-vdso.so.1 (0x00007ffd9a0a7000)
    libssl.so.1.0.0 => /usr/lib64/libssl.so.1.0.0 (0x00007f947cc7e000)
    libcrypto.so.1.0.0 => /usr/lib64/libcrypto.so.1.0.0 (0x00007f947c8ae000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f947c6aa000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f947c3b1000)
    libz.so.1 => /lib64/libz.so.1 (0x00007f947c19b000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f947be03000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f947cee9000)

-static 表示您希望所有静态链接。然后您需要将所有库准备为静态，结果将是:

$ ldd test
    not a dynamic executable