VistaIOWarning(3) report a nonfatal error

Other Alias



void VistaIOWarning (format [, arg...])

void VistaIOSystemWarning (format [, arg...])


Specifies the format of the message that is to be reported.

Specifies values that are to be included in the formatted message.


VistaIOWarning is called to report a nonfatal error. It composes an error message and passes it to the nonfatal error handler, which typically prints the message and returns (see VistaIOSetWarningHandler(3)).

The message composed by VistaIOWarning is of the form:

Program: Warning: Description.

Program, the program's name, is included if it has been previously established with a call to VistaIOSetProgramName. Description is a string that has been formatted by sprintf using format, plus all of the optional arguments, arg.

VistaIOSystemWarning is identical to VistaIOWarning except that it also includes in the message a phrase based on the current value of the external variable errno, which is used by system calls to return diagnostic codes. The message composed by VistaIOSystemWarning is of the form:

Program: Warning: Description: Diagnostic.

Diagnostic is a short phrase corresponding to the value of errno. This phrase is drawn from the table used by perror(3).


In this first example, the values of attr_name, act_value, and exp_value are incorporated into the error message produced by VistaIOWarning.

char *attr_name;
float act_value, exp_value;
if (act_value != exp_value)
        VistaIOWarning ("MyRoutine: Attribute %s is %f rather than %f",
                attr_name, act_value, exp_value);

In this second example, the diagnostic phrase corresponding to the value of errno is incorporated into the error message produced by VistaIOSystemWarning.

if (ioctl (fd, request, arg) == -1)
        VistaIOSystemWarning ("MyRoutine: ioctl failed");


Art Pope <[email protected]>

Adaption to vistaio: Gert Wollny <[email protected]>