#pragma diag_default tag[,tag,...]

Where:

// <stdio.h> not #included deliberately

#pragma diag_error 223
void hello(void)
{
    printf("Hello ");
}

#pragma diag_default 223
void world(void)
{
    printf("world!\n");
}

Compiling this code with the option --diag_warning=223 generates diagnostic messages to report that the function printf() is declared implicitly.

The effect of #pragma diag_default 223 is to return the severity of diagnostic message 223 to Warning severity, as specified by the --diag_warning command-line option.