FMTMSG(3)                  POSIX Programmer's Manual                 FMTMSG(3)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       fmtmsg -- display a message in the specified format on standard error
       and/or a system console

SSYYNNOOPPSSIISS
       #include <fmtmsg.h>

       int fmtmsg(long _c_l_a_s_s_i_f_i_c_a_t_i_o_n, const char *_l_a_b_e_l, int _s_e_v_e_r_i_t_y,
           const char *_t_e_x_t, const char *_a_c_t_i_o_n, const char *_t_a_g);

DDEESSCCRRIIPPTTIIOONN
       The _f_m_t_m_s_g() function shall display messages in a specified format
       instead of the traditional _p_r_i_n_t_f() function.

       Based on a message's classification component, _f_m_t_m_s_g() shall write a
       formatted message either to standard error, to the console, or to both.

       A formatted message consists of up to five components as defined below.
       The component _c_l_a_s_s_i_f_i_c_a_t_i_o_n is not part of a message displayed to the
       user, but defines the source of the message and directs the display of
       the formatted message.

       _c_l_a_s_s_i_f_i_c_a_t_i_o_n
                   Contains the sum of identifying values constructed from the
                   constants defined below. Any one identifier from a subclass
                   may be used in combination with a single identifier from a
                   different subclass. Two or more identifiers from the same
                   subclass should not be used together, with the exception of
                   identifiers from the display subclass. (Both display
                   subclass identifiers may be used so that messages can be
                   displayed to both standard error and the system console.)

                   MMaajjoorr CCllaassssiiffiiccaattiioonnss
                         Identifies the source of the condition. Identifiers
                         are: MM_HARD (hardware), MM_SOFT (software), and
                         MM_FIRM (firmware).

                   MMeessssaaggee SSoouurrccee SSuubbccllaassssiiffiiccaattiioonnss
                         Identifies the type of software in which the problem
                         is detected.  Identifiers are: MM_APPL (application),
                         MM_UTIL (utility), and MM_OPSYS (operating system).

                   DDiissppllaayy SSuubbccllaassssiiffiiccaattiioonnss
                         Indicates where the message is to be displayed.
                         Identifiers are: MM_PRINT to display the message on
                         the standard error stream, MM_CONSOLE to display the
                         message on the system console. One or both
                         identifiers may be used.

                   SSttaattuuss SSuubbccllaassssiiffiiccaattiioonnss
                         Indicates whether the application can recover from
                         the condition.  Identifiers are: MM_RECOVER
                         (recoverable) and MM_NRECOV (non-recoverable).

                   An additional identifier, MM_NULLMC, indicates that no
                   classification component is supplied for the message.

       _l_a_b_e_l       Identifies the source of the message. The format is two
                   fields separated by a <colon>.  The first field is up to 10
                   bytes, the second is up to 14 bytes.

       _s_e_v_e_r_i_t_y    Indicates the seriousness of the condition. Identifiers for
                   the levels of _s_e_v_e_r_i_t_y are:

                   MM_HALT     Indicates that the application has encountered
                               a severe fault and is halting. Produces the
                               string ""HHAALLTT"".

                   MM_ERROR    Indicates that the application has detected a
                               fault. Produces the string ""EERRRROORR"".

                   MM_WARNING  Indicates a condition that is out of the
                               ordinary, that might be a problem, and should
                               be watched. Produces the string ""WWAARRNNIINNGG"".

                   MM_INFO     Provides information about a condition that is
                               not in error. Produces the string ""IINNFFOO"".

                   MM_NOSEV    Indicates that no severity level is supplied
                               for the message.

       _t_e_x_t        Describes the error condition that produced the message.
                   The character string is not limited to a specific size. If
                   the character string is empty, then the text produced is
                   unspecified.

       _a_c_t_i_o_n      Describes the first step to be taken in the error-recovery
                   process.  The _f_m_t_m_s_g() function precedes the action string
                   with the prefix: ""TTOOFIX:"..  The _a_c_t_i_o_n string is not
                   limited to a specific size.

       _t_a_g         An identifier that references on-line documentation for the
                   message.  Suggested usage is that _t_a_g includes the _l_a_b_e_l
                   and a unique identifying number. A sample _t_a_g is
                   ""XXSSII::ccaatt::114466"".

       The _M_S_G_V_E_R_B environment variable (for message verbosity) shall
       determine for _f_m_t_m_s_g() which message components it is to select when
       writing messages to standard error. The value of _M_S_G_V_E_R_B shall be a
       <colon>-separated list of optional keywords. Valid keywords are: _l_a_b_e_l,
       _s_e_v_e_r_i_t_y, _t_e_x_t, _a_c_t_i_o_n, and _t_a_g. If _M_S_G_V_E_R_B contains a keyword for a
       component and the component's value is not the component's null value,
       _f_m_t_m_s_g() shall include that component in the message when writing the
       message to standard error. If _M_S_G_V_E_R_B does not include a keyword for a
       message component, that component shall not be included in the display
       of the message. The keywords may appear in any order. If _M_S_G_V_E_R_B is not
       defined, if its value is the null string, if its value is not of the
       correct format, or if it contains keywords other than the valid ones
       listed above, _f_m_t_m_s_g() shall select all components.

       _M_S_G_V_E_R_B shall determine which components are selected for display to
       standard error. All message components shall be included in console
       messages.

RREETTUURRNN VVAALLUUEE
       The _f_m_t_m_s_g() function shall return one of the following values:

       MM_OK       The function succeeded.

       MM_NOTOK    The function failed completely.

       MM_NOMSG    The function was unable to generate a message on standard
                   error, but otherwise succeeded.

       MM_NOCON    The function was unable to generate a console message, but
                   otherwise succeeded.

EERRRROORRSS
       None.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
        1. The following example of _f_m_t_m_s_g():


               fmtmsg(MM_PRINT, "XSI:cat", MM_ERROR, "illegal option",
               "refer to cat in user's reference manual", "XSI:cat:001")

           produces a complete message in the specified message format:


               XSI:cat: ERROR: illegal option
               TO FIX: refer to cat in user's reference manual XSI:cat:001

        2. When the environment variable _M_S_G_V_E_R_B is set as follows:


               MSGVERB=severity:text:action

           and Example 1 is used, _f_m_t_m_s_g() produces:


               ERROR: illegal option
               TO FIX: refer to cat in user's reference manual

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       One or more message components may be systematically omitted from
       messages generated by an application by using the null value of the
       argument for that component.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_p_r_i_n_t_f()

       The Base Definitions volume of POSIX.1-2017, <<ffmmttmmssgg..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                            FMTMSG(3)
