error

<html> <head> <title>error</title> <META NAME="KEYWORDS" CONTENT="error"> </head> <body BGCOLOR="#ffffff" LINK="#0000ff" VLINK="#0000ff" ALINK="#0000ff" TEXT="#000000"> <center> <h1>error</h1></center> <PRE> <A HREF="/man3/ERROR">ERROR(3)</A> Linux Programmer's Manual <A HREF="/man3/ERROR">ERROR(3)</A> NAME error, error_at_line, error_message_count, error_one_per_line, er- ror_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 <A HREF="/man3/printf">printf(3)</A>-style format string format, and, if er- rnum 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 <A HREF="/man3/program_invocation_name">program_invocation_name(3)</A>. 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 <A HREF="/man3/exit">exit(3)</A> 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 at- <A HREF="/man7/tributes">tributes(7)</A>. +----------------+---------------+-----------------------------------+ |Interface | Attribute | Value | +----------------+---------------+-----------------------------------+ |error() | Thread safety | MT-Safe locale | +----------------+---------------+-----------------------------------+ |error_at_line() | Thread safety | MT-Unsafe race: error_at_line/er- | | | | ror_one_per_line locale | +----------------+---------------+-----------------------------------+ 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 <A HREF="/man3/err">err(3)</A>, <A HREF="/man3/errno">errno(3)</A>, <A HREF="/man3/exit">exit(3)</A>, <A HREF="/man3/perror">perror(3)</A>, <A HREF="/man3/program_invocation_name">program_invocation_name(3)</A>, str- <A HREF="/man3/error">error(3)</A> COLOPHON This page is part of release 5.05 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 <A HREF="/man3/ERROR">ERROR(3)</A></PRE> <center> <h6>Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2025 <a href="http://www.he.net">Hurricane Electric</a>. All Rights Reserved.</h6></center> </body> </html>

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