ERROR
NAME
error, error_at_line, error_message_count, error_on_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
R error ()
is a general error reporting function.
It flushes
R 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
non-zero, a second colon and a space followed by the string given by
perror(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
R error ()
is the value of the global variable
program_invocation_name(3).
R program_invocation_name
initially has the same value as
R main ()'s
R argv[0] .
The value of this variable can be modified to change the output of
R error ().
If
status has a non-zero value, then
R error ()
calls
exit(3)
to terminate the program using the given value as the exit status.
The
R error_at_line ()
function is exactly the same as
R error (),
except for the addition of the arguments
filename
and
R linenum .
The output produced is as for
R error (),
except that after the program name are written: a colon, the value of
R filename ,
a colon, and the value of
R linenum .
The preprocessor values
__LINE__ and
__FILE__ may be useful when calling
R 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 non-zero,
a sequence of
R 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
R error ()
and
R 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
R stderr .
CONFORMING TO
These functions and variables are GNU extensions, and should not be
used in programs intended to be portable.
SEE ALSO
ČLÁNKY DO MAILU