NAME

       curl_global_trace - Global libcurl logging configuration

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_global_trace(const char *config);

DESCRIPTION

       This function configures the logging behavior, allowing to make some parts of curl more verbose or silent
       than others.

       This  function may be called during the initialization phase of a program. It does not have to be. It can
       be called several times even, possibly overwriting settings of previous calls.

       Calling this function after transfers have been started is undefined. On some platforms/architectures  it
       might take effect, on others not.

       This  function is thread-safe since libcurl 8.3.0 if curl_version_info(3) has the CURL_VERSION_THREADSAFE
       feature bit set (most platforms).

       If this is not thread-safe, you must not call this function when any other thread in the program (i.e.  a
       thread  sharing  the  same  memory)  is  running.   This does not just mean no other thread that is using
       libcurl. Because curl_global_init(3) may call functions of other  libraries  that  are  similarly  thread
       unsafe, it could conflict with any other thread that uses these other libraries.

       If  you are initializing libcurl from a Windows DLL you should not initialize it from DllMain or a static
       initializer because Windows holds the loader lock during that time and it could cause a deadlock.

       The config string is a list of comma-separated component names. Names are  case-insensitive  and  unknown
       names  are  ignored.  The special name "all" applies to all components. Names may be prefixed with '+' or
       '-' to enable or disable detailed logging for a component.

       The list of component names is not part of curl's public API. Names may be added or disappear  in  future
       versions of libcurl. Since unknown names are silently ignored, outdated log configurations does not cause
       errors  when upgrading libcurl. Given that, some names can be expected to be fairly stable and are listed
       below for easy reference.

       Note  that  log  configuration  applies  only  to  transfers  where  debug  logging   is   enabled.   See
       CURLOPT_VERBOSE(3) or CURLOPT_DEBUGFUNCTION(3) on how to control that.

TRACE COMPONENTS

       tcp    Tracing of TCP socket handling: connect, reads, writes.

       ssl    Tracing of SSL/TLS operations, whichever SSL backend is used in your build.

       http/2 Details about HTTP/2 handling: frames, events, I/O, etc.

       http/3 Details about HTTP/3 handling: connect, frames, events, I/O etc.

       http-proxy
              Involved  when  transfers  are  tunneled  through  a HTTP proxy. "h1-proxy" or "h2-proxy" are also
              involved, depending on the HTTP version negotiated with the proxy.

              In order to find out all components involved in a transfer, run it with "all" configured. You  can
              then see all names involved in your libcurl version in the trace.

EXAMPLE

       int main(void)
       {
         /* log details of HTTP/2 and SSL handling */
         curl_global_trace("http/2,ssl");

         /* log all details, except SSL handling */
         curl_global_trace("all,-ssl");
       }

       Below  is  a trace sample where "http/2" was configured. The trace output of an enabled component appears
       at the beginning in brackets.
       * [HTTP/2] [h2sid=1] cf_send(len=96) submit https://example.com/
       ...
       * [HTTP/2] [h2sid=1] FRAME[HEADERS]
       * [HTTP/2] [h2sid=1] 249 header bytes
       ...

AVAILABILITY

       Added in 8.3

RETURN VALUE

       If this function returns non-zero, something went wrong and the configuration may not have any effects or
       may only been applied partially.

SEE ALSO

       curl_global_init(3), libcurl(3)

libcurl 8.5.0                                   December 04, 2023                           curl_global_trace(3)