Description:
------------
When I have to manage a long number in the header, the __soapCall function returns a float number in exponential format. The original sent value can't be retrieved and the returned one is different.

Reproduce code:
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A Java server sends a sessionID in the header with the following value : 339051398236687110
This is the client code :

    $soapclient->__soapCall('beginSession',$parameters, null, null, $header);
    echo $header["sessionID"]; // returns 3.3905139823669E+17 , an  
                               // invalid value for the next call
                               // and with less digits than required
    $strNum = number_format($header["sessionID"], 0, "", "");
    echo $strNum;              // returns the rounded value
                               // 339051398236687050 , that is 
                               // different from the original
                               // 339051398236687110

 

Expected result:
----------------
The header has to contain 339051398236687110

Actual result:
--------------
The header contain 3.3905139823669E+17