vlfmt(3c) - osol9

1vlfmt(3C)                Standard C Library Functions                vlfmt(3C)
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NAME

6       vlfmt  -  display  error message in standard format and pass to logging
7       and monitoring services
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SYNOPSIS

10       #include <pfmt.h>
11       #include <stdarg.h>
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13       int vlfmt(FILE *stream, long flag, const char *format, va_list ap);
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DESCRIPTION

17       The vlfmt() function is identical to lfmt(3C), except that it is called
18       with an argument list as defined by <stdarg.h>.
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21       The  <stdarg.h> header defines the type va_list and a set of macros for
22       advancing through a list of arguments whose number and types may  vary.
23       The  ap  argument  is  of  type va_list. This argument is used with the
24       <stdarg.h> macros va_start(), va_arg(), and va_end(). See stdarg(3EXT).
25       The  example  in the EXAMPLES section below demonstrates their use with
26       vlfmt().
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RETURN VALUES

29       Upon successful completion, vlfmt() returns the number of bytes  trans‐
30       mitted.   Otherwise,  −1  is  returned  if  there  was a write error to
31       stream, or −2 is returned if unable to log and/or display at console.
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EXAMPLES

34       Example 1 Use of vlfmt() to write an errlog()routine.
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37       The following example demonstrates how vlfmt() could be used  to  write
38       an errlog() routine. The va_alist() macro is used as the parameter list
39       in a function definition. The va_start(ap, ...) call, where  ap  is  of
40       type va_list, must be invoked before any attempt to traverse and access
41       unnamed arguments. Calls to va_arg(ap,  atype)  traverse  the  argument
42       list.  Each  execution  of  va_arg()  expands to an expression with the
43       value and type of the next argument in the list ap, which is  the  same
44       object  initialized  by va_start(). The atype argument is the type that
45       the returned argument is expected to be. The va_end(ap) macro  must  be
46       invoked  when  all  desired  arguments have been accessed. The argument
47       list in ap can be traversed again if va_start() is called  again  after
48       va_end().) In the example below, va_arg() is executed first to retrieve
49       the format string passed to errlog(). The remaining errlog()  arguments
50       (arg1, arg2, ...) are passed to vlfmt() in the argument ap.
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53         #include <pfmt.h>
54         #include <stdarg.h>
55         /*
56          *   errlog should be called like
57          *         errlog(log_info, format, arg1, ...);
58          */
59         void errlog(long log_info, ...)
60         {
61                 va_list ap;
62                 char *format;
63                 va_start(ap, );
64                 format = va_arg(ap, char *);
65                 (void) vlfmt(stderr, log_info|MM_ERROR, format, ap);
66                 va_end(ap);
67                 (void) abort();
68         }
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USAGE

72       Since  vlfmt()  uses  gettxt(3C), it is recommended that vlfmt() not be
73       used.
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ATTRIBUTES

76       See attributes(5) for descriptions of the following attributes:
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81       ┌─────────────────────────────┬─────────────────────────────┐
82       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
83       ├─────────────────────────────┼─────────────────────────────┤
84       │MT-Level                     │MT-Safe                      │
85       └─────────────────────────────┴─────────────────────────────┘
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