Lots of people download binary distributions of curl and libcurl. This document does not describe how to install curl or libcurl using such a binary package. This document describes how to compile, build and install curl and libcurl from source code.
If you get your code off a git repository instead of a release tarball, see
the GIT-INFO
file in the root directory for specific instructions on how to
proceed.
A normal Unix installation is made in three or four steps (after you've unpacked the source archive):
./configure
make
make test (optional)
make install
You probably need to be root when doing the last command.
Get a full listing of all available configure options by invoking it like:
./configure --help
If you want to install curl in a different file hierarchy than /usr/local
,
specify that when running configure:
./configure --prefix=/path/to/curl/tree
If you have write permission in that directory, you can do 'make install' without being root. An example of this would be to make a local install in your own home directory:
./configure --prefix=$HOME
make
make install
The configure script always tries to find a working SSL library unless
explicitly told not to. If you have OpenSSL installed in the default search
path for your compiler/linker, you don't need to do anything special. If you
have OpenSSL installed in /usr/local/ssl
, you can run configure like:
./configure --with-ssl
If you have OpenSSL installed somewhere else (for example, /opt/OpenSSL
) and
you have pkg-config installed, set the pkg-config path first, like this:
env PKG_CONFIG_PATH=/opt/OpenSSL/lib/pkgconfig ./configure --with-ssl
Without pkg-config installed, use this:
./configure --with-ssl=/opt/OpenSSL
If you insist on forcing a build without SSL support, even though you may have OpenSSL installed in your system, you can run configure like this:
./configure --without-ssl
If you have OpenSSL installed, but with the libraries in one place and the header files somewhere else, you have to set the LDFLAGS and CPPFLAGS environment variables prior to running configure. Something like this should work:
CPPFLAGS="-I/path/to/ssl/include" LDFLAGS="-L/path/to/ssl/lib" ./configure
If you have shared SSL libs installed in a directory where your run-time linker doesn't find them (which usually causes configure failures), you can provide this option to gcc to set a hard-coded path to the run-time linker:
LDFLAGS=-Wl,-R/usr/local/ssl/lib ./configure --with-ssl
To force a static library compile, disable the shared library creation by running configure like:
./configure --disable-shared
To tell the configure script to skip searching for thread-safe functions, add an option like:
./configure --disable-thread
If you're a curl developer and use gcc, you might want to enable more debug
options with the --enable-debug
option.
curl can be built to use a whole range of libraries to provide various useful services, and configure will try to auto-detect a decent default. But if you want to alter it, you can select how to deal with each individual library.
The default OpenSSL configure check will also detect and use BoringSSL or libressl.
--without-ssl --with-gnutls
.--without-ssl --with-wolfssl
--without-ssl --with-nss
--without-ssl --with-polarssl
--without-ssl --with-mbedtls
--without-ssl --with-schannel
--without-ssl --with-secure-transport
--without-ssl --with-mesalink
As a general rule, building a DLL with static CRT linkage is highly discouraged, and intermixing CRTs in the same app is something to avoid at any cost.
Reading and comprehending Microsoft Knowledge Base articles KB94248 and KB140584 is a must for any Windows developer. Especially important is full understanding if you are not going to follow the advice given above.
If your app is misbehaving in some strange way, or it is suffering from memory corruption, before asking for further help, please try first to rebuild every single library your app uses as well as your app using the debug multithreaded dynamic C runtime.
If you get linkage errors read section 5.7 of the FAQ document.
Make sure that MinGW32's bin dir is in the search path, for example:
set PATH=c:\mingw32\bin;%PATH%
then run mingw32-make mingw32
in the root dir. There are other
make targets available to build libcurl with more features, use:
mingw32-make mingw32-zlib
to build with Zlib support;mingw32-make mingw32-ssl-zlib
to build with SSL and Zlib enabled;mingw32-make mingw32-ssh2-ssl-zlib
to build with SSH2, SSL, Zlib;mingw32-make mingw32-ssh2-ssl-sspi-zlib
to build with SSH2, SSL, Zlib
and SSPI support.If you have any problems linking libraries or finding header files, be sure to verify that the provided "Makefile.m32" files use the proper paths, and adjust as necessary. It is also possible to override these paths with environment variables, for example:
set ZLIB_PATH=c:\zlib-1.2.8
set OPENSSL_PATH=c:\openssl-1.0.2c
set LIBSSH2_PATH=c:\libssh2-1.6.0
It is also possible to build with other LDAP SDKs than MS LDAP; currently it is possible to build with native Win32 OpenLDAP, or with the Novell CLDAP SDK. If you want to use these you need to set these vars:
set LDAP_SDK=c:\openldap
set USE_LDAP_OPENLDAP=1
or for using the Novell SDK:
set USE_LDAP_NOVELL=1
If you want to enable LDAPS support then set LDAPS=1.
Almost identical to the unix installation. Run the configure script in the
curl source tree root with sh configure
. Make sure you have the sh
executable in /bin/ or you'll see the configure fail toward the end.
Run make
The configure utility, unfortunately, is not available for the Windows environment, therefore, you cannot use the various disable-protocol options of the configure utility on this platform.
However, you can use the following defines to disable specific protocols:
HTTP_ONLY
disables all protocols except HTTPCURL_DISABLE_FTP
disables FTPCURL_DISABLE_LDAP
disables LDAPCURL_DISABLE_TELNET
disables TELNETCURL_DISABLE_DICT
disables DICTCURL_DISABLE_FILE
disables FILECURL_DISABLE_TFTP
disables TFTPCURL_DISABLE_HTTP
disables HTTPCURL_DISABLE_IMAP
disables IMAPCURL_DISABLE_POP3
disables POP3CURL_DISABLE_SMTP
disables SMTPIf you want to set any of these defines you have the following options:
Note: The pre-processor settings can be found using the Visual Studio IDE under "Project -> Settings -> C/C++ -> General" in VC6 and "Project -> Properties -> Configuration Properties -> C/C++ -> Preprocessor" in later versions.
In order to compile libcurl and curl using BSD-style lwIP TCP/IP stack it is necessary to make definition of preprocessor symbol USE_LWIPSOCK visible to libcurl and curl compilation processes. To set this definition you have the following alternatives:
Note: The pre-processor settings can be found using the Visual Studio IDE under "Project -> Settings -> C/C++ -> General" in VC6 and "Project -> Properties -> Configuration Properties -> C/C++ -> Preprocessor" in later versions.
Once that libcurl has been built with BSD-style lwIP TCP/IP stack support, in
order to use it with your program it is mandatory that your program includes
lwIP header file <lwip/opt.h>
(or another lwIP header that includes this)
before including any libcurl header. Your program does not need the
USE_LWIPSOCK
preprocessor definition which is for libcurl internals only.
Compilation has been verified with lwIP 1.4.0 and contrib-1.4.0.
This BSD-style lwIP TCP/IP stack support must be considered experimental given that it has been verified that lwIP 1.4.0 still needs some polish, and libcurl might yet need some additional adjustment, caveat emptor.
When building an application that uses the static libcurl library on Windows,
you must add -DCURL_STATICLIB
to your CFLAGS
. Otherwise the linker will
look for dynamic import symbols.
WinSSL (specifically Schannel from Windows SSPI), is the native SSL library in Windows. However, WinSSL in Windows <= XP is unable to connect to servers that no longer support the legacy handshakes and algorithms used by those versions. If you will be using curl in one of those earlier versions of Windows you should choose another SSL backend such as OpenSSL.
On modern Apple operating systems, curl can be built to use Apple's SSL/TLS
implementation, Secure Transport, instead of OpenSSL. To build with Secure
Transport for SSL/TLS, use the configure option --with-darwinssl
. (It is not
necessary to use the option --without-ssl
.) This feature requires iOS 5.0 or
later, or OS X 10.5 ("Leopard") or later.
When Secure Transport is in use, the curl options --cacert
and --capath
and their libcurl equivalents, will be ignored, because Secure Transport uses
the certificates stored in the Keychain to evaluate whether or not to trust
the server. This, of course, includes the root certificates that ship with the
OS. The --cert
and --engine
options, and their libcurl equivalents, are
currently unimplemented in curl with Secure Transport.
For OS X users: In OS X 10.8 ("Mountain Lion"), Apple made a major overhaul to
the Secure Transport API that, among other things, added support for the newer
TLS 1.1 and 1.2 protocols. To get curl to support TLS 1.1 and 1.2, you must
build curl on Mountain Lion or later, or by using the equivalent SDK. If you
set the MACOSX_DEPLOYMENT_TARGET
environmental variable to an earlier
version of OS X prior to building curl, then curl will use the new Secure
Transport API on Mountain Lion and later, and fall back on the older API when
the same curl binary is executed on older cats. For example, running these
commands in curl's directory in the shell will build the code such that it
will run on cats as old as OS X 10.6 ("Snow Leopard") (using bash):
export MACOSX_DEPLOYMENT_TARGET="10.6"
./configure --with-darwinssl
make
Download and unpack the curl package.
'cd' to the new directory. (e.g. cd curl-7.12.3
)
Set environment variables to point to the cross-compile toolchain and call
configure with any options you need. Be sure and specify the --host
and
--build
parameters at configuration time. The following script is an
example of cross-compiling for the IBM 405GP PowerPC processor using the
toolchain from MonteVista for Hardhat Linux.
#! /bin/sh
export PATH=$PATH:/opt/hardhat/devkit/ppc/405/bin
export CPPFLAGS="-I/opt/hardhat/devkit/ppc/405/target/usr/include"
export AR=ppc_405-ar
export AS=ppc_405-as
export LD=ppc_405-ld
export RANLIB=ppc_405-ranlib
export CC=ppc_405-gcc
export NM=ppc_405-nm
./configure --target=powerpc-hardhat-linux
--host=powerpc-hardhat-linux
--build=i586-pc-linux-gnu
--prefix=/opt/hardhat/devkit/ppc/405/target/usr/local
--exec-prefix=/usr/local
You may also need to provide a parameter like --with-random=/dev/urandom
to
configure as it cannot detect the presence of a random number generating
device for a target system. The --prefix
parameter specifies where curl
will be installed. If configure
completes successfully, do make
and make
install
as usual.
In some cases, you may be able to simplify the above commands to as little as:
./configure --host=ARCH-OS
There are a number of configure options that can be used to reduce the size of
libcurl for embedded applications where binary size is an important factor.
First, be sure to set the CFLAGS variable when configuring with any relevant
compiler optimization flags to reduce the size of the binary. For gcc, this
would mean at minimum the -Os option, and potentially the -march=X
,
-mdynamic-no-pic
and -flto
options as well, e.g.
./configure CFLAGS='-Os' LDFLAGS='-Wl,-Bsymbolic'...
Note that newer compilers often produce smaller code than older versions due to improved optimization.
Be sure to specify as many --disable-
and --without-
flags on the
configure command-line as you can to disable all the libcurl features that you
know your application is not going to need. Besides specifying the
--disable-PROTOCOL
flags for all the types of URLs your application will not
use, here are some other flags that can reduce the size of the library:
--disable-ares
(disables support for the C-ARES DNS library)--disable-cookies
(disables support for HTTP cookies)--disable-crypto-auth
(disables HTTP cryptographic authentication)--disable-ipv6
(disables support for IPv6)--disable-manual
(disables support for the built-in documentation)--disable-proxy
(disables support for HTTP and SOCKS proxies)--disable-unix-sockets
(disables support for UNIX sockets)--disable-verbose
(eliminates debugging strings and error code strings)--disable-versioned-symbols
(disables support for versioned symbols)--enable-hidden-symbols
(eliminates unneeded symbols in the shared library)--without-libidn
(disables support for the libidn DNS library)--without-librtmp
(disables support for RTMP)--without-ssl
(disables support for SSL/TLS)--without-zlib
(disables support for on-the-fly decompression)The GNU compiler and linker have a number of options that can reduce the size of the libcurl dynamic libraries on some platforms even further. Specify them by providing appropriate CFLAGS and LDFLAGS variables on the configure command-line, e.g.
CFLAGS="-Os -ffunction-sections -fdata-sections
-fno-unwind-tables -fno-asynchronous-unwind-tables -flto"
LDFLAGS="-Wl,-s -Wl,-Bsymbolic -Wl,--gc-sections"
Be sure also to strip debugging symbols from your binaries after compiling using 'strip' (or the appropriate variant if cross-compiling). If space is really tight, you may be able to remove some unneeded sections of the shared library using the -R option to objcopy (e.g. the .comment section).
Using these techniques it is possible to create a basic HTTP-only shared libcurl library for i386 Linux platforms that is only 113 KiB in size, and an FTP-only library that is 113 KiB in size (as of libcurl version 7.50.3, using gcc 5.4.0).
You may find that statically linking libcurl to your application will result in a lower total size than dynamically linking.
Note that the curl test harness can detect the use of some, but not all, of
the --disable
statements suggested above. Use will cause tests relying on
those features to fail. The test harness can be manually forced to skip the
relevant tests by specifying certain key words on the runtests.pl command
line. Following is a list of appropriate key words:
--disable-cookies
!cookies--disable-manual
!--manual--disable-proxy
!HTTP\ proxy !proxytunnel !SOCKS4 !SOCKS5This is a probably incomplete list of known hardware and operating systems that curl has been compiled for. If you know a system curl compiles and runs on, that isn't listed, please let us know!