Am 16.05.2015 um 00:37 schrieb Enrico Forestieri <for...@lyx.org>: > On Fri, May 15, 2015 at 04:58:24PM +0200, Stephan Witt wrote: > >> Am 15.05.2015 um 16:48 schrieb Enrico Forestieri <for...@lyx.org>: >> >>> On Fri, May 15, 2015 at 04:31:05PM +0200, Stephan Witt wrote: >>>> >>>> This results in the following patch - if you had something like that in >>>> mind I'll split it in two patches. The other getPixmap method with >>>> QPixmap result was already there. >>> >>> Yes, I think that it is better passing big objects by reference rather >>> than by value. >> >> But this is not a good property of C++ compilers than. >> 1. It's not a constant fact if an object is big. >> 2. The compiler should generate fast code for this scenario too. >> 3. This results in hard to read code eventually. > > You are probably right and it seems people prefer the simpler approach by > relying on the return value optimization performed by modern compilers. > http://stackoverflow.com/questions/753312/returning-large-objects-in-functions > http://stackoverflow.com/questions/4809120/creating-and-returning-a-big-object-from-a-function > http://stackoverflow.com/questions/24685054/how-do-c-functions-return-a-big-object-or-a-structure > > What triggered my comment was seeing that call in a loop, so you could simply > limit the change to that one function and leave the rest as is. Or you could > also disregard that comment ;-)
:) I'm unsure - with the previous code returning a pixmap missing pixmaps are ignored silently. With the change proposed by Enrico it is easy to add a error or warning message. The price is the change of many files containing a call to the getPixmap() method. Is there anyone having an opinion about this topic? Stephan
