Warning, /FWCore/MessageService/doc/preambleMode.txt is written in an unsupported language. File is not indexed.
0001 The workings of ELoutput::preambleMode
0002 --------------------------------------
0003
0004 (A MessageLogger maintenance document)
0005
0006
0007 preambleMode is a data member of the ELoutput destination class.
0008
0009 Its use is in emitToken:
0010 void ELoutput::emitToken( const ELstring & s, bool nl ) { ...
0011
0012 The first tokens may be of a header nature, in which
0013 case certain line control and other processing is done. That is indicated
0014 if preambleMode is true; otherwise the token s is output without further ado.
0015
0016 preambleMode is established in several places. The key one is in
0017 bool ELoutput::log( const edm::ErrorObj & msg ) {...
0018 which sets it true **regardless of incoming value**, does whatever header work
0019 is specified by configuration information, and sets it false before
0020 emitting the ordinary items in the message string.
0021
0022 In each ctor, it is also established. Prior to Sept 2 2010 the code
0023 looked like:
0024
0025 ELoutput::ELoutput( std::ostream & os_ , bool emitAtStart ) {
0026 if (emitAtStart) {
0027 bool tprm = preambleMode;
0028 preambleMode = true;
0029 emitToken( "\n=================================================", true );
0030 emitToken( "\nMessage Log File written by MessageLogger service \n" );
0031 emitToken( "\n=================================================\n", true );
0032 preambleMode = tprm;
0033 }
0034
0035 Note that the value used for those emitToken calls is invariably true;
0036 note also that whatever value preambleMode had coming in was preserved,
0037 only to be wiped out by the first log call. Therefore, the use of tprm
0038 was unnecessary. Moreover, it was technically use of an unititialized
0039 data member.
0040
0041 Two possible choices for a fix could have been considered: Initializing
0042 preambleMode (to true) in the initializer list, or removing the use of
0043 tprm. Since we are going to the trouble of initializing all the other data
0044 members, as is good coding form, we did the former fix, initializing
0045 preambleMode (to true) in the initializer list for each ctor. We also
0046 removed the now-completely-superfluous code using tprm.
0047
0048
