Disable single warning error

Question

#pragma warning( push )
#pragma warning( disable : 4101)
// Your function
#pragma warning( pop ) 

If you only want to suppress a warning in a single line of code (after preprocessing)[1], you can use the suppress warning specifier:

#pragma warning(suppress: 4101)
// here goes your single line of code where the warning occurs

For a single line of code, this works the same as writing the following:

#pragma warning(push)
#pragma warning(disable: 4101)
// here goes your code where the warning occurs
#pragma warning(pop)

[1] Others have noted in comments below that if the following statement is an #include statement that the #pragma warning(suppress: 4101) statement would not effectively suppress the warning for every line in the header file. If one were intending to do that, one would need to utilize the push/disable/pop method instead.

#pragma push/pop are often a solution for this kind of problems, but in this case why don't you just remove the unreferenced variable?

try
{
    // ...
}
catch(const your_exception_type &) // type specified but no variable declared
{
    // ...
}

Use #pragma warning ( push ), then #pragma warning ( disable ), then put your code, then use #pragma warning ( pop ) as described here:

#pragma warning( push )
#pragma warning( disable : WarningCode)
// code with warning
#pragma warning( pop ) 

Example:

#pragma warning(suppress:0000)  // (suppress one error in the next line)

This pragma is valid for C++ starting with Visual Studio 2005.
https://msdn.microsoft.com/en-us/library/2c8f766e(v=vs.80).aspx

The pragma is NOT valid for C# through Visual Studio 2005 through Visual Studio 2015.
Error: "Expected disable or restore".
(I guess they never got around to implementing suppress ...)
https://msdn.microsoft.com/en-us/library/441722ys(v=vs.140).aspx

C# needs a different format. It would look like this (but not work):

#pragma warning suppress 0642  // (suppress one error in the next line)

Instead of suppress, you have to disable and enable:

if (condition)
#pragma warning disable 0642
    ;  // Empty statement HERE provokes Warning: "Possible mistaken empty statement" (CS0642)
#pragma warning restore 0642
else

That is SO ugly, I think it is smarter to just re-style it:

if (condition)
{
    // Do nothing (because blah blah blah).
}
else

as @rampion mentioned, if you are in clang gcc, the warnings are by name, not number, and you'll need to do:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-variable"
// ..your code..
#pragma clang diagnostic pop

this info comes from here

Instead of putting it on top of the file (or even a header file), just wrap the code in question with #pragma warning (push), #pragma warning (disable) and a matching #pragma warning (pop), as shown here.

Although there are some other options, including #pramga warning (once).