cURL / Mailing Lists / curl-library / Single Mail


binary mode on Win32 but LF becomes CRLF

From: Rowe David W. <>
Date: Mon, 7 Jun 2004 16:26:04 -0500

I have been having a problem with a binary mode transfer on Win32.
I have a cgi program which will retrieve a file with http and write it
to stdout.
I have set the mode of stdout to binary.
All LFs are being converted to CRLF pairs.

I have found that by setting the CURLOPT_WRITEFUNCTION to fwrite with
CURLOPT_WRITEDATA set to stdout the problem goes away. (See code
fragment below.)

I have thought of 3 possible explanations:
1: libcurl is working properly but I don't understand how it is supposed
to work
2: Something went wrong when I built libcurl (i.e. it is just me)
3: This is a bug

Any insight as to why this is happening would be greatly appreciated. It
would be nice to hear whether or not it should work without these

Setting CURLOPT_TRANSFERTEXT and CURLOPT_CRLF has had no effect.

This occurs with 7.11.2 and 7.12.0.
As an aside I needed to add
to "project settings\link\project options" in VC6 to build 7.12.0.

Code fragment follows:

if ( _setmode( _fileno( stdout ), _O_BINARY ) == -1 )
        ErrorPage("<B>Couldn't set stdout to binary.</B>\n");

        CURL *curl;
        CURLcode res;

        res = curl_global_init(CURL_GLOBAL_ALL);

        curl = curl_easy_init();

        if( res != CURLE_OK || curl == NULL )
                ErrorPage("<B>Couldn't initialize cURL.</B>\n");

                curl_easy_setopt(curl, CURLOPT_HEADER, TRUE);

                curl_easy_setopt(curl, CURLOPT_URL, pszURL);

                //without the next two lines LFs become CRLFs
                curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite);
                curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void
                res = curl_easy_perform(curl);

Received on 2004-06-07