The Warning Disable Pragma

Some warning messages can be disabled by using the warning disable pragma.

This pragma will only affect warnings that are produced by the parser or the code generator; i.e., errors directly associated with C code. The position of the pragma is only significant for the parser; i.e., a parser warning number can be disabled for one section of the code to target specific instances of the warning. Specific instances of a warning produced by the code generator cannot be individually controlled and the pragma will remain in force during compilation of the entire C program, even across modules.

Those warnings that have been disabled can be preserved and recalled using the warning push and warning pop pragmas. The warning push and warning pop pragmas can be nested.

The following example normally produces the warning associated with assignment of a const object address to a pointer to non-const objects (359).

int readp(int * ip) {
    return *ip;
}
const int i = 'd';
int main(void) {
    unsigned char c;
#pragma warning disable 359
    readp(&i);
#pragma warning enable 359
}

This same effect would be observed using the following code.

#pragma warning push
#pragma warning disable 359
    readp(&i);
#pragma warning pop

Here, the state of the messaging system is saved by the warning push pragma. Warning 359 is disabled, then after the source code which triggers the warning, the state of the messaging system is retrieved by using the warning pop pragma.