_ _ ____ _ ___| | | | _ \| | / __| | | | |_) | | | (__| |_| | _ <| |___ \___|\___/|_| \_\_____| FAQ Problems connecting to SSL servers. =================================== It took a very long time before I could sort out why curl had problems to connect to certain SSL servers when using SSLeay or OpenSSL v0.9+. The error sometimes showed up similar to: 16570:error:1407D071:SSL routines:SSL2_READ:bad mac decode:s2_pkt.c:233: It turned out to be because many older SSL servers don't deal with SSLv3 requests properly. To correct this problem, tell curl to select SSLv2 from the command line (-2/--sslv2). I have also seen examples where the remote server didn't like the SSLv2 request and instead you had to force curl to use SSLv3 with -3/--sslv3. Does curl support resume? ========================= Yes. Both ways on FTP, download ways on HTTP. Is libcurl thread safe? ======================= Yes, as far as curl's own code goes. It does use system calls that often aren't thread safe in most environments, such as gethostbyname(). I am very interested in once and for all getting some kind of report or README file from those who have used libcurl in a threaded environment, since I haven't and I get this question more and more frequently! Why doesn't my posting using -F work? ===================================== You can't simply use -F or -d at your choice. The web server that will receive your post assumes one of the formats. If the form you're trying to "fake" sets the type to 'multipart/form-data', than and only then you must use the -F type. In all the most common cases, you should use -d which then causes a posting with the type 'application/x-www-form-urlencoded'. Does curl support custom FTP commands? ====================================== Yes it does, you can tell curl to perform optional commands both before and/or after a file transfer. Study the -Q/--quote option. Since curl is used for file transfers, you don't use curl to just perform ftp commands without transfering anything. Therefore you must always specify a URL to transfer to/from even when doing custom FTP commands. Does curl work with other SSL libraries? ======================================== Curl has been written to use OpenSSL, although I doubt there would be much problems using a different library. I just don't know any other free one and that has limited my possibilities to develop against anything else. If anyone does "port" curl to use a commercial SSL library, I am of course very interested in getting the patch! configre doesn't find OpenSSL even when it is installed ======================================================= Platforms: Solaris (native cc compiler) and HPUX (native cc compiler) When configuring curl, I specify --with-ssl. OpenSSL is installed in /usr/local/ssl Configure reports SSL in /usr/local/ssl, but fails to find CRYPTO_lock in -lcrypto Cause: The cc for this test places the -L/usr/local/ssl/lib AFTER -lcrypto, so ld can't find the library. This is due to a bug in the GNU autoconf tool. Workaround: Specifying "LDFLAGS=-L/usr/local/ssl/lib" in front of ./configure places the -L/usr/local/ssl/lib early enough in the command line to make things work Submitted by: Bob Allison