NAME

       explain_wait3 - explain wait3(2) errors

SYNOPSIS

       #include <libexplain/wait3.h>
       const char *explain_wait3(int *status, int options, struct rusage *rusage);
       const  char  *explain_errno_wait3(int  errnum,  int  *status,  int  options, struct rusage
       *rusage);
       void explain_message_wait3(char *message, int  message_size,  int  *status,  int  options,
       struct rusage *rusage);
       void explain_message_errno_wait3(char *message, int message_size, int errnum, int *status,
       int options, struct rusage *rusage);

DESCRIPTION

       These functions may be used to obtain explanations for errors  returned  by  the  wait3(2)
       system call.

   explain_wait3
       const char *explain_wait3(int *status, int options, struct rusage *rusage);

       The  explain_wait3  function  is used to obtain an explanation of an error returned by the
       wait3(2) system call.  The least the message will contain is the value of strerror(errno),
       but usually it will do much better, and indicate the underlying cause in more detail.

       The errno global variable will be used to obtain the error value to be decoded.

       This function is intended to be used in a fashion similar to the following example:
              int pid = wait3(status, options, rusage);
              if (pid < 0)
              {
                  fprintf(stderr, "%s\n", explain_wait3(status, options, rusage));
                  exit(EXIT_FAILURE);
              }

       status  The original status, exactly as passed to the wait3(2) system call.

       options The original options, exactly as passed to the wait3(2) system call.

       rusage  The original rusage, exactly as passed to the wait3(2) system call.

       Returns:
               The message explaining the error.  This message buffer is shared by all libexplain
               functions which do not supply a buffer in  their  argument  list.   This  will  be
               overwritten  by the next call to any libexplain function which shares this buffer,
               including other threads.

       Note: This function is not thread safe, because it  shares  a  return  buffer  across  all
       threads, and many other functions in this library.

   explain_errno_wait3
       const  char  *explain_errno_wait3(int  errnum,  int  *status,  int  options, struct rusage
       *rusage);

       The explain_errno_wait3 function is used to obtain an explanation of an error returned  by
       the  wait3(2)  system  call.   The  least  the  message  will  contain  is  the  value  of
       strerror(errnum), but usually it will do much better, and indicate the underlying cause in
       more detail.

       This function is intended to be used in a fashion similar to the following example:
              int pid = wait3(status, options, rusage);
              if (pid < 0)
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_wait3(err, status, options,
                      rusage));
                  exit(EXIT_FAILURE);
              }

       errnum  The  error  value  to  be decoded, usually obtained from the errno global variable
               just before this function is called.  This is necessary if you need  to  call  any
               code  between the system call to be explained and this function, because many libc
               functions will alter the value of errno.

       status  The original status, exactly as passed to the wait3(2) system call.

       options The original options, exactly as passed to the wait3(2) system call.

       rusage  The original rusage, exactly as passed to the wait3(2) system call.

       Returns:
               The message explaining the error.  This message buffer is shared by all libexplain
               functions  which  do  not  supply  a  buffer in their argument list.  This will be
               overwritten by the next call to any libexplain function which shares this  buffer,
               including other threads.

       Note:  This  function  is  not  thread  safe, because it shares a return buffer across all
       threads, and many other functions in this library.

   explain_message_wait3
       void explain_message_wait3(char *message, int  message_size,  int  *status,  int  options,
       struct rusage *rusage);

       The  explain_message_wait3  function  may  be  used  to  obtain an explanation of an error
       returned by the wait3(2) system call.  The least the message will contain is the value  of
       strerror(errno),  but usually it will do much better, and indicate the underlying cause in
       more detail.

       The errno global variable will be used to obtain the error value to be decoded.

       This function is intended to be used in a fashion similar to the following example:
              int pid = wait3(status, options, rusage);
              if (pid < 0)
              {
                  char message[3000];
                  explain_message_wait3(message, sizeof(message),
                      status, options, rusage);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       message The location in which to store the returned message.  If a suitable message return
               buffer is supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned message.

       status  The original status, exactly as passed to the wait3(2) system call.

       options The original options, exactly as passed to the wait3(2) system call.

       rusage  The original rusage, exactly as passed to the wait3(2) system call.

   explain_message_errno_wait3
       void explain_message_errno_wait3(char *message, int message_size, int errnum, int *status,
       int options, struct rusage *rusage);

       The explain_message_errno_wait3 function may be used to obtain an explanation of an  error
       returned  by the wait3(2) system call.  The least the message will contain is the value of
       strerror(errnum), but usually it will do much better, and indicate the underlying cause in
       more detail.

       This function is intended to be used in a fashion similar to the following example:
              int pid = wait3(status, options, rusage);
              if (pid < 0)
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_wait3(message, sizeof(message), err,
                      status, options, rusage);
                  fprintf(stderr, "%s\n", message);
                  exit(EXIT_FAILURE);
              }

       message The location in which to store the returned message.  If a suitable message return
               buffer is supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned message.

       errnum  The error value to be decoded, usually obtained from  the  errno  global  variable
               just  before  this  function is called.  This is necessary if you need to call any
               code between the system call to be explained and this function, because many  libc
               functions will alter the value of errno.

       status  The original status, exactly as passed to the wait3(2) system call.

       options The original options, exactly as passed to the wait3(2) system call.

       rusage  The original rusage, exactly as passed to the wait3(2) system call.

SEE ALSO

       wait3(2)
               wait for process to change state

       explain_wait3_or_die(3)
               wait for process to change state and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2008 Peter Miller

                                                                                 explain_wait3(3)