NAME

       errormsg, set_progname, get_progname - printing error messages

SYNOPSIS

       #include <errormsg.h>

       void errormsg(int exitp, int eno, const char *fmt, ...);
       void set_progname(const char *argv0, const char *def);
       const char *get_progname(void);

DESCRIPTION

       The  errormsg function is used for printing error messages.  It is a like a combination of fprintf(3) and
       perror(3), in that it makes it easy to add arbitrary, printf-like formatted text to the output, and makes
       it  easy  to  include  the  system's error message (the error string corresponding to the eno parameter).
       Unlike perror, this function does not get the error code directly from errno, thus making it easier to do
       something  else  that might set it before printing out the error message.  errormsg also adds the name of
       the program to the output, if known.

       The first argument to errormsg should be 0 (don't exit program), 1 (exit program with exit(EXIT_FAILURE))
       or  2  (with  abort()).   The  second one should be 0 (don't print system error message), positive (print
       error message corresponding to the error code), or -1 (print the error message corresponding to errno).

       The set_progname function sets the program name.  You need to call this function with at least  one  non-
       NULL  parameter  to  get  the  program  names included in the output.  If either argument is non-NULL, it
       should point at strings that have static duration, i.e. they exist until the program  terminates  (or  at
       least  until  the  last  error message has been printed); this is so that it is not necessary to create a
       copy of the name.  (Either or both arguments can also be NULL.)

       If the first argument is non-NULL, that is used as the name, otherwise the seconds argument is used.   If
       both are NULL, no program name is included in the output.  The reason for having two arguments is so that
       the caller doesn't have to do the test, and can just call

                 set_progname(argv[0], "default_name");

       (it is valid for argv[0] to be NULL, under ISO C).

       The get_progname function returns a pointer to the current name of the program, as set  by  set_progname.
       If  get_progname  returns  NULL,  then  no  name  has  been set and none is included in the output.  This
       function is included for completeness, it is not really expected to be useful.

SEE ALSO

       publib(3)

AUTHOR

       Lars Wirzenius (lars.wirzenius@helsinki.fi)

                                                                                                  ERRORMSG(3pub)