### warn_implicitconv

Controls the issuing of warnings for all implicit arithmetic conversions.

##### Syntax

#pragma warn_implicitconv on | off | reset

##### Targets

All platforms.

##### Remarks

If you enable this pragma, the compiler issues a warning for all implicit arithmetic conversions when the destination type might not represent the source value. Listing 10.40 provides an example.

#### Listing 10.40 Example of Implicit Conversion

#pragma warn_implicitconv on // required to enable warnings
#pragma warn_impl_f2i_conv on // enable conversion warning
#pragma warn_impl_i2f_conv on // enable conversion warning
#pragma warn_impl_s2u_conv on // enable conversion warning

float f;
signed int si;
unsigned int ui;

int main()
{
f = si; // WARNING
si = f; // WARNING
ui = si; // WARNING
si = ui; // WARNING
}

For more information about this warning, see “Implicit Arithmetic Conversions”.

NOTE This option “opens the gate” for the checking of implicit conversions. The sub-pragmas warn_impl_f2i_conv, warn_impl_i2f_conv, and warn_impl_s2u_conv control the classes of conversions checked.

This pragma corresponds to the Implicit Arithmetic Conversions setting . To check this setting, use __option (warn_implicitconv), described in Checking Settings. The default setting is off.