NAME

       error,   error_at_line,  error_message_count,  error_one_per_line,  error_print_progname  -  glibc  error
       reporting functions

SYNOPSIS

       #include <error.h>

       void error(int status, int errnum, const char *format, ...);

       void error_at_line(int status, int errnum, const char *filename,
                          unsigned int linenum, const char *format, ...);

       extern unsigned int error_message_count;

       extern int error_one_per_line;

       extern void (*error_print_progname) (void);

DESCRIPTION

       error() is a general error-reporting function.  It flushes stdout, and then outputs to stderr the program
       name, a colon and a space, the message specified by the printf(3)-style format  string  format,  and,  if
       errnum  is  nonzero,  a  second  colon and a space followed by the string given by strerror(errnum).  Any
       arguments required for format should follow format in the argument list.  The output is terminated  by  a
       newline character.

       The  program  name  printed  by  error()  is the value of the global variable program_invocation_name(3).
       program_invocation_name initially has the same value as main()'s argv[0].  The value of this variable can
       be modified to change the output of error().

       If status has a nonzero value, then error() calls exit(3) to terminate the program using the given  value
       as the exit status.

       The  error_at_line()  function  is  exactly the same as error(), except for the addition of the arguments
       filename and linenum.  The output produced is as for error(), except that  after  the  program  name  are
       written:  a  colon,  the  value  of filename, a colon, and the value of linenum.  The preprocessor values
       __LINE__ and __FILE__ may be useful when calling error_at_line(), but other values can also be used.  For
       example, these arguments could refer to a location in an input file.

       If the global variable error_one_per_line is set nonzero, a sequence of error_at_line()  calls  with  the
       same value of filename and linenum will result in only one message (the first) being output.

       The  global  variable  error_message_count counts the number of messages that have been output by error()
       and error_at_line().

       If the global variable error_print_progname is assigned the address of a function (i.e.,  is  not  NULL),
       then  that  function  is  called  instead  of prefixing the message with the program name and colon.  The
       function should print a suitable string to stderr.

CONFORMING TO

       These functions and variables are GNU extensions, and should not be  used  in  programs  intended  to  be
       portable.

SEE ALSO

       err(3), errno(3), exit(3), perror(3), program_invocation_name(3), strerror(3)

COLOPHON

       This  page  is  part  of  release 3.54 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

GNU                                                2010-08-29                                           ERROR(3)