Pragma directives

The #pragma preprocessing directive is used to specify optional contextual information to the compiler. The information supplied in a #pragma directive will never change program semantics.

pp-pragma:
whitespace_opt # whitespace_opt pragma whitespace pragma-body pp-new-line

pragma-body:
pragma-warning-body

C# provides #pragma directives to control compiler warnings. Future versions of the language may include additional #pragma directives. To ensure interoperability with other C# compilers, the Microsoft C# compiler does not issue compilation errors for unknown #pragma directives; such directives do however generate warnings.

2.5.8.1 Pragma warning

The #pragma warning directive is used to disable or restore all or a particular set of warning messages during compilation of the subsequent program text.

pragma-warning-body:
warning whitespace warning-action
warning whitespace warning-action whitespace warning-list

warning-action:
disable
restore

warning-list:
decimal-digits
warning-list whitespace_opt, whitespace_opt decimal-digits

A #pragma warning directive that omits the warning list affects all warnings. A #pragma warning directive the includes a warning list affects only those warnings that are specified in the list.

A #pragma warning disable directive disables all or the given set of warnings.

A #pragma warning restore directive restores all or the given set of warnings to the state that was in effect at the beginning of the compilation unit. Note that if a particular warning was disabled externally, a #pragma warning restore (whether for all or the specific warning) will not re-enable that warning.

The following example shows use of #pragma warning to temporarily disable the warning reported when obsoleted members are referenced, using the warning number from the Microsoft C# compiler.

using System;

class Program
{
[Obsolete]
static void Foo() {}

static void Main() {
#pragma warning disable 612
Foo();
#pragma warning restore 612
}
}