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.\" **************************************************************************
.\" * _ _ ____ _
.\" * Project ___| | | | _ \| |
.\" * / __| | | | |_) | |
.\" * | (__| |_| | _ <| |___
.\" * \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.TH libcurl-env-dbg 3 "18 September 2023" "libcurl" "libcurl"
.SH NAME
libcurl-env-dbg \- environment variables libcurl DEBUGBUILD understands
.SH DESCRIPTION
This is a set of variables only recognized and used if libcurl was built
"debug enabled", which should never be true for a library used in production.
These variables are intended for internal use only, subject to change and have
many effects on the behavior of libcurl. Refer to the source code to determine
how exactly they are being used.
.RS
.IP "CURL_ALTSVC_HTTP"
Bypass the AltSvc HTTPS protocol restriction if this variable exists.
.IP "CURL_DBG_SOCK_RBLOCK"
The percentage of recv() calls that should be answered with a EAGAIN at random.
For TCP/UNIX sockets.
.IP "CURL_DBG_SOCK_RMAX"
The maximum data that shall be received from the network in one recv() call.
For TCP/UNIX sockets. This is applied to every recv.
Example: \fBCURL_DBG_SOCK_RMAX=400\fP means recv buffer size is limited to a
maximum of 400 bytes.
.IP "CURL_DBG_SOCK_WBLOCK"
The percentage of send() calls that should be answered with a EAGAIN at random.
For TCP/UNIX sockets.
.IP "CURL_DBG_SOCK_WPARTIAL"
The percentage of data that shall be written to the network. For TCP/UNIX
sockets. This is applied to every send.
Example: \fBCURL_DBG_SOCK_WPARTIAL=80\fP means a send with 1000 bytes would
only send 800.
.IP "CURL_DBG_QUIC_WBLOCK"
The percentage of send() calls that should be answered with EAGAIN at random.
QUIC only.
.IP "CURL_DEBUG"
Trace logging behavior as an alternative to calling \fIcurl_global_trace(3)\fP.
Example: \fBCURL_DEBUG=http/2\fP means trace details about HTTP/2 handling.
.IP "CURL_DEBUG_SIZE"
Fake the size returned by CURLINFO_HEADER_SIZE and CURLINFO_REQUEST_SIZE.
.IP "CURL_GETHOSTNAME"
Fake the local machine's unqualified hostname for NTLM and SMTP.
.IP "CURL_HSTS_HTTP"
Bypass the HSTS HTTPS protocol restriction if this variable exists.
.IP "CURL_FORCETIME"
A time of 0 is used for AWS signatures and NTLM if this variable exists.
.IP "CURL_ENTROPY"
A fixed faked value to use instead of a proper random number so that functions
in libcurl that are otherwise getting random outputs can be tested for what
they generate.
.IP "CURL_SMALLREQSEND"
An alternative size of HTTP data to be sent at a time only if smaller than the
current.
.IP "CURL_SMALLSENDS"
An alternative size of socket data to be sent at a time only if smaller than
the current.
.IP "CURL_TIME"
Fake unix timestamp to use for AltSvc, HSTS and CURLINFO variables that are
time related.
This variable can also be used to fake the data returned by some CURLINFO
variables that are not time-related (such as CURLINFO_LOCAL_PORT), and in that
case the value is not a timestamp.
.IP "CURL_TRACE"
LDAP tracing is enabled if this variable exists and its value is 1 or greater.
OpenLDAP tracing is separate. Refer to CURL_OPENLDAP_TRACE.
.IP "CURL_NTLM_WB_FILE"
Debug-version of the \fIntlm-wb\fP executable.
.IP "CURL_OPENLDAP_TRACE"
OpenLDAP tracing is enabled if this variable exists and its value is 1 or
greater. There's a number of debug levels, refer to \fIopenldap.c\fP comments.
.RE
.SH "SEE ALSO"
.BR libcurl-env (3)
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