16 Jan
2012
16 Jan
'12
6:52 p.m.
Is'nt that "else" keyword adding
ambigiusity, reason why this thread
exists? Furthermore: depending of the compiler and
optimisation, I suppose
that code could be added because the "else" keyword
existance.
I'm not qualified to answer your coding question, but with reference to why this
thread exists, I never stated my reason. :) My reason is I was browsing the code of
tdelibs/kio/kio/kdirwatch.cpp in the hopes of seeing something obvious to help resolve bug
report 756. As I am learning C++, one of the functions in that cpp caught my attention. I
wanted to know how multiple return statements within a function operate. Here is the
particular snippet from line 707:
====================================================
#ifdef HAVE_INOTIFY
// setup INotify notification, returns false if not possible
bool KDirWatchPrivate::useINotify( Entry* e )
{
e->wd = 0;
e->dirty = false;
if (!supports_inotify) return false;
e->m_mode = INotifyMode;
int mask = IN_DELETE|IN_DELETE_SELF|IN_CREATE|IN_MOVE|IN_MOVE_SELF|IN_DONT_FOLLOW;
if(!e->isDir)
mask |= IN_MODIFY|IN_ATTRIB;
else
mask |= IN_ONLYDIR;
// if dependant is a file watch, we check for MODIFY & ATTRIB too
for(Entry* dep=e->m_entries.first();dep;dep=e->m_entries.next()) {
if (!dep->isDir) { mask |= IN_MODIFY|IN_ATTRIB; break; }
}
if ( ( e->wd = inotify_add_watch( m_inotify_fd,
TQFile::encodeName( e->path ), mask) ) > 0 )
return true;
if ( e->m_status == NonExistent ) {
if (e->isDir)
addEntry(0, TQDir::cleanDirPath(e->path+"/.."), e, true);
else
addEntry(0, TQFileInfo(e->path).dirPath(true), e, true);
return true;
}
return false;
}
#endif
====================================================
There are four return statements in that function, two true and two false. I have been
told that a function stops executing upon any return statement. That is good enough for
me. If that was incorrect then I would read the snippet as always returning false because
that is the last statement in the function. I did not think that was correct and my texts
provided me no clues. Therefore I asked the question to be sure. Now I know that any of
three return statements prior to the final return statement will cause the function to
exit and return that assigned boolean value.
For those itching to hack some code and become a hero, bug report 756 identifies several
items when Konqueror fails to update the file pane when a file changes state.
Darrell