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)