GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


man:error_one_per_line

ERROR(3) Linux Programmer's Manual ERROR(3)

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 mes-
     sage 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 new-
     line 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 mod-
     ified 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 pro-
     duced is as for error(), except that after the program name  are  writ-
     ten: a colon, the value of filename, a colon, and the value of linenum.
     The preprocessor values __LINE__ and __FILE__ may be useful when  call-
     ing  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.

ATTRIBUTES

     For  an  explanation  of  the  terms  used   in   this   section,   see
     attributes(7).
     allbox; lb lb lbw33 l l l.  Interface Attribute Value T{ error()
     T}   Thread safety   MT-Safe locale T{ error_at_line() T}   Thread
     safety  T{ MT-Unsafe race: error_at_line/error_one_per_line locale T}
     The  internal error_one_per_line variable is accessed (without any form
     of synchronization, but since it's an int used once, it should be  safe
     enough)  and, if error_one_per_line is set nonzero, the internal static
     variables (not exposed to users) used to hold the last printed filename
     and  line number are accessed and modified without synchronization; the
     update is not atomic and it occurs before disabling cancellation, so it
     can  be  interrupted  only  after one of the two variables is modified.
     After that, error_at_line() is very much like error().

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), str-
     error(3)

COLOPHON

     This page is part of release 4.16 of the Linux  man-pages  project.   A
     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 ERROR(3)

/data/webs/external/dokuwiki/data/pages/man/error_one_per_line.txt · Last modified: 2019/05/17 09:47 by 127.0.0.1

Was this page helpful?-10+1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki