CODEWITHSUNDEEP
c++visual-studiodebuggingvisual-studio-debugging
Joe
Joe

Reputation: 881

Visual Studio (C++) debugging in debug mode vs release mode

I'm new to windows development, and my programming skills are not that strong (I'm with EE background, major is semiconductor), but at least I understand the fundamental of C/C++.

Regarding Windows C++ project, I found that I can debug under both debug and release builds (by adding break points, and reading the value of variables) in visual studio. I did some research, and I found that as long as there is a PDB file, I can do the debugging. However, will the "debug-able" release build impact the performance?

I also read about disabling debug in visual C++ projects. If I disable debugging, will the performance of a release build be better than a debug-enabled release build?

Sorry for my broken English.

Upvotes: 3

Views: 1464

Answers (3)

Hans Passant
Hans Passant

Reputation: 942399

No, it makes no difference. The linker's /DEBUG option is simply turned off by default for the Release build. The PDB it generates isn't all that useful for debugging, the optimizer that's turned on for the Release build makes a big ole mess of your debugging session. You'll have trouble setting breakpoints on some statements, see single-stepping acting weird (the code highlight moving around unpredictably) and the debugger not being able to show you variable values.

Still, sometimes you really need the PDB file, invaluable when you get a minidump back. Recorded by a customer when your program crashed and burned a thousand miles away. You need to plan for that, pretty important to generate the PDBs and store them so you'll have them available when you analyze the minidump.

Upvotes: 4

JaredPar
JaredPar

Reputation: 755507

A binary can be debugged in windows with or without a PDB file. A PDB is a database of sort which provides information to the debugger such as the name of locals, the type of locals, offset to source mapping, etc .... None of this is strictly necessary to debug it just makes it a whole lot nicer. If you were so inclined you could debug the assembly directly with no PDB.

Hence there is really no concept of "disabling debugging". Really it comes down to whether you build a Debug / Release build. A Debug build is generally much more debuggable than a Release build because the compiler will take care to keep interesting locals around and insert no-ops to make stepping nicer. Release builds are all about performance of the final output and will sacrifice easy debugging to achieve it

Upvotes: 0

RichieHindle
RichieHindle

Reputation: 281845

Enabling PDB generation doesn't affect code generation, so the performance of your Release code won't change if you enable PDBs.

(Do note that debugging of optimised code is not as reliable as debugging non-optimised code... you'll find that the current line seems to jump around, and that you can't always rely on the reported values of variables.)

Upvotes: 3

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