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explain_execv(3)	   Library Functions Manual	      explain_execv(3)

NAME
       explain_execv - explain execv(3)	errors

SYNOPSIS
       #include	<libexplain/execv.h>
       const char *explain_execv(const char *pathname, char *const*argv);
       const char *explain_errno_execv(int errnum, const char *pathname, char
       *const*argv);
       void explain_message_execv(char *message, int message_size, const char
       *pathname, char *const*argv);
       void explain_message_errno_execv(char *message, int message_size, int
       errnum, const char *pathname, char *const*argv);

DESCRIPTION
       These functions may be used to obtain explanations for errors  returned
       by the execv(3) system call.

   explain_execv
       const char *explain_execv(const char *pathname, char *const*argv);

       The explain_execv function is used to obtain an explanation of an error
       returned	by the execv(3)	system call. The least the message  will  con-
       tain  is	the value of strerror(errno), but usually it will do much bet-
       ter, and	indicate the underlying	cause in more detail.

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

       pathname
	       The original pathname, exactly as passed	to the execv(3)	system
	       call.

       argv    The original argv, exactly as passed  to	 the  execv(3)	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 buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (execv(pathname, argv)	< 0)
	      {
		  fprintf(stderr, "%s\n", explain_execv(pathname, argv));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is available pre-packaged as the explain_ex-
       ecv_or_die(3) function.

   explain_errno_execv
       const char *explain_errno_execv(int errnum, const char *pathname, char
       *const*argv);

       The explain_errno_execv function	is used	to obtain an explanation of an
       error returned by the execv(3) 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.

       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.

       pathname
	       The original pathname, exactly as passed	to the execv(3)	system
	       call.

       argv    The  original  argv,  exactly  as passed	to the execv(3)	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 buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (execv(pathname, argv)	< 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_execv(err, pathname,
		  argv));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is available pre-packaged as the explain_ex-
       ecv_or_die(3) function.

   explain_message_execv
       void explain_message_execv(char *message, int message_size, const char
       *pathname, char *const*argv);

       The  explain_message_execv function is used to obtain an	explanation of
       an error	returned by the	execv(3) 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.

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

       message_size
	       The  size  in  bytes  of	the location in	which to store the re-
	       turned message.

       pathname
	       The original pathname, exactly as passed	to the execv(3)	system
	       call.

       argv    The  original  argv,  exactly  as passed	to the execv(3)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (execv(pathname, argv)	< 0)
	      {
		  char message[3000];
		  explain_message_execv(message, sizeof(message), pathname,
		  argv);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The above code example is available  pre-packaged  as  the  explain_ex-
       ecv_or_die(3) function.

   explain_message_errno_execv
       void explain_message_errno_execv(char *message, int message_size, int
       errnum, const char *pathname, char *const*argv);

       The explain_message_errno_execv function	is used	to obtain an  explana-
       tion  of	 an  error returned by the execv(3) 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.

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

       message_size
	       The  size  in  bytes  of	the location in	which to store the re-
	       turned 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.

       pathname
	       The original pathname, exactly as passed	to the execv(3)	system
	       call.

       argv    The  original  argv,  exactly  as passed	to the execv(3)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (execv(pathname, argv)	< 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_execv(message, sizeof(message),	err,
		  pathname, argv);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The above code example is available  pre-packaged  as  the  explain_ex-
       ecv_or_die(3) function.

SEE ALSO
       execv(3)
	       execute a file

       explain_execv_or_die(3)
	       execute a file and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2012 Peter	Miller

							      explain_execv(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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