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



NAME
       err,  verr,  errx,  verrx, warn, vwarn, warnx, vwarnx - formatted error
       messages

SYNOPSIS
       #include <&lt;err.h>&gt;

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

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

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

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

       #include <&lt;stdarg.h>&gt;

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

DESCRIPTION
       The err() and warn() family of functions display a formatted error mes-
       sage on the standard error output.  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(), verr(), warn(), and vwarn() functions append an  error  mes-
       sage  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.

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

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

       The err(), verr(), errx(), and verrx() functions  do  not  return,  but
       exit with the value of the argument eval.

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);

CONFORMING TO
       These functions are non-standard BSD extensions.

SEE ALSO
       error(3), exit(3), perror(3), printf(3), strerror(3)

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2007-12-28                            ERR(3)