bool

       MongoDB, Inc

       2009-present, MongoDB, Inc.

1.30.4                                            Jun 08, 2025                   MONGOC_HANDSHAKE_DATA_APPEND(3)

       This  function  is intended for use by drivers which wrap the C Driver.  Calling this function will store
       the given strings as handshake data about the system and driver by appending them to the  handshake  data
       for  the  underlying C Driver. These values, along with other handshake data collected during mongoc_init
       will be sent to the server as part of the initial connection handshake in  the  "client"  document.  This
       function  must  not  be  called  more than once, or after server monitoring begins. For a single-threaded
       mongoc_client_t,  server  monitoring  begins  on  the  first  operation  requiring  a   server.   For   a
       mongoc_client_pool_t, server monitoring begins on the first call to :symbol:`mongoc_client_pool_pop.

       The   passed   in   strings   are   copied,   and   don't   have  to  remain  valid  after  the  call  to
       mongoc_handshake_data_append(). The driver may store truncated versions of the passed in strings.

       NOTE:
          This function allocates memory, and therefore caution should be used when using  this  in  conjunction
          with   bson_mem_set_vtable().  If  this  function  is  called  before  bson_mem_set_vtable(),  then  ‐
          bson_mem_restore_vtable() must be called before calling mongoc_cleanup(). Failure to do so will result
          in memory being freed by the wrong allocator.

       • driver_name: An optional string storing the name of the wrapping driver

       • driver_version: An optional string storing the version of the wrapping driver.

       • platform: An optional string storing any information about the current platform, for example  configure
         options or compile flags.

true if the given fields are set successfully. Otherwise, it returns false and logs an error.

       The default handshake data the driver sends with "hello" looks something like:

          client: {
            driver: {
              name: "mongoc",
              version: "1.5.0"
            },
            os: {...},
            platform: "CC=gcc CFLAGS=-Wall -pedantic"
          }

       If  we  call  mongoc_handshake_data_append()  ("phongo", "1.1.8", "CC=clang / ") and it returns true, the
       driver sends handshake data like:

          client: {
            driver: {
              name: "mongoc / phongo",
              version: "1.5.0 / 1.1.8"
            },
            os: {...},
            platform: "CC=clang / gcc CFLAGS=-Wall -pedantic"
          }

          bool
          mongoc_handshake_data_append (const char *driver_name,
                                        const char *driver_version,
                                        const char *platform);

       Appends the given strings to the handshake data for the underlying C Driver.