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errc (3)

>> errc (3) ( FreeBSD man: Библиотечные вызовы )

BSD mandoc

NAME



err

 
verr

 
errc

 
verrc

 
errx

 
verrx

 
warn

 
vwarn

 
warnc

 
vwarnc

 
warnx

 
vwarnx

 
err_set_exit

 
err_set_file

 - formatted error messages

LIBRARY

Lb libc

SYNOPSIS

#include <err.h>
void err (int eval const char *fmt ...);
void err_set_exit (void (*exitf)(int));
void err_set_file (void *vfp);
void errc (int eval int code const char *fmt ...);
void errx (int eval const char *fmt ...);
void warn (const char *fmt ...);
void warnc (int code const char *fmt ...);
void warnx (const char *fmt ...);
#include <stdarg.h>
void verr (int eval const char *fmt va_list args);
void verrc (int eval int code const char *fmt va_list args);
void verrx (int eval const char *fmt va_list args);
void vwarn (const char *fmt va_list args);
void vwarnc (int code const char *fmt va_list args);
void vwarnx (const char *fmt va_list args);

DESCRIPTION

The err ();
and warn ();
family of functions display a formatted error message on the standard error output, or on another file specified using the err_set_file ();
function. In all cases, the last component of the program name, a colon character, and a space are output. If the Fa fmt argument is not NULL, the printf(3) -like formatted error message is output. The output is terminated by a newline character.

The err (,);
errc (,);
verr (,);
verrc (,);
warn (,);
warnc (,);
vwarn (,);
and vwarnc ();
functions append an error message obtained from strerror(3) based on a supplied error code value or the global variable errno preceded by another colon and space unless the Fa fmt argument is NULL

In the case of the errc (,);
verrc (,);
warnc (,);
and vwarnc ();
functions, the Fa code argument is used to look up the error message.

The err (,);
verr (,);
warn (,);
and vwarn ();
functions use the global variable errno to look up the error message.

The errx ();
and warnx ();
functions do not append an error message.

The err (,);
verr (,);
errc (,);
verrc (,);
errx (,);
and verrx ();
functions do not return, but exit with the value of the argument Fa eval . It is recommended that the standard values defined in sysexits(3) be used for the value of Fa eval . The err_set_exit ();
function can be used to specify a function which is called before exit(3) to perform any necessary cleanup; passing a null function pointer for exitf resets the hook to do nothing. The err_set_file ();
function sets the output stream used by the other functions. Its Fa vfp argument must be either a pointer to an open stream (possibly already converted to void *) or a null pointer (in which case the output stream is set to standard error).

EXAMPLES

Display the current errno information string and exit:

if ((p = malloc(size)) == NULL)
        err(1, NULL);
if ((fd = open(file_name, O_RDONLY, 0)) == -1)
        err(1, "%s", file_name);

Display an error message and exit:

if (tm.tm_hour < START_TIME)
        errx(1, "too early, wait until %s", start_time_string);

Warn of an error:

if ((fd = open(raw_device, O_RDONLY, 0)) == -1)
        warnx("%s: %s: trying the block device",
            raw_device, strerror(errno));
if ((fd = open(block_device, O_RDONLY, 0)) == -1)
        err(1, "%s", block_device);

Warn of an error without using the global variable errno

error = my_function();  /* returns a value from <errno.h> */
if (error != 0)
        warnc(error, "my_function");

HISTORY

The err ();
and warn ();
functions first appeared in BSD 4.4 The err_set_exit ();
and err_set_file ();
functions first appeared in Fx 2.1 . The errc ();
and warnc ();
functions first appeared in Fx 3.0 .

Партнёры:

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Created 1996-2024 by Maxim Chirkov
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