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NAME    [Toc]    [Back]

     err, verr, errc, verrc, errx, verrx, warn, vwarn, warnc, vwarnc, warnx,
     vwarnx, err_set_exit, err_set_file -- formatted error messages

LIBRARY    [Toc]    [Back]

     Standard C Library (libc, -lc)

SYNOPSIS    [Toc]    [Back]

     #include <err.h>

     err(int eval, const char *fmt, ...);

     err_set_exit(void (*exitf)(int));

     err_set_file(void *vfp);

     errc(int eval, int code, const char *fmt, ...);

     errx(int eval, const char *fmt, ...);

     warn(const char *fmt, ...);

     warnc(int code, const char *fmt, ...);

     warnx(const char *fmt, ...);

     #include <stdarg.h>

     verr(int eval, const char *fmt, va_list args);

     verrc(int eval, int code, const char *fmt, va_list args);

     verrx(int eval, const char *fmt, va_list args);

     vwarn(const char *fmt, va_list args);

     vwarnc(int code, const char *fmt, va_list args);

     vwarnx(const char *fmt, va_list args);

DESCRIPTION    [Toc]    [Back]

     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 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 code or the global variable errno, preceded by another colon
     and space unless the fmt argument is NULL.

     In the case of the errc(), verrc(), warnc(), and vwarnc() functions, the
     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 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 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

EXAMPLES    [Toc]    [Back]

     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");

SEE ALSO    [Toc]    [Back]

     exit(3), fmtmsg(3), printf(3), strerror(3)

HISTORY    [Toc]    [Back]

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

FreeBSD 5.2.1			 March 6, 1999			 FreeBSD 5.2.1
[ Back ]
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