Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
explain_strtol(3)	   Library Functions Manual	     explain_strtol(3)

NAME
       explain_strtol -	explain	strtol(3) errors

SYNOPSIS
       #include	<libexplain/strtol.h>
       const char *explain_strtol(const	char *nptr, char **endptr, int base);
       const char *explain_errno_strtol(int errnum, const char *nptr, char
       **endptr, int base);
       void explain_message_strtol(char	*message, int message_size, const char
       *nptr, char **endptr, int base);
       void explain_message_errno_strtol(char *message,	int message_size, int
       errnum, const char *nptr, char **endptr,	int base);

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

   explain_strtol
       const char *explain_strtol(const	char *nptr, char **endptr, int base);

       The  explain_strtol function is used to obtain an explanation of	an er-
       ror returned by the strtol(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.

       nptr    The  original  nptr,  exactly as	passed to the strtol(3)	system
	       call.

       endptr  The original endptr, exactly as passed to the strtol(3)	system
	       call.

       base    The  original  base,  exactly as	passed to the strtol(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:
	      long result = strtol(nptr, endptr, base);
	      if (result < 0)
	      {
		  fprintf(stderr, "%s\n", explain_strtol(nptr, endptr, base));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_strtol
       const char *explain_errno_strtol(int errnum, const char *nptr, char
       **endptr, int base);

       The explain_errno_strtol	function is used to obtain an  explanation  of
       an  error  returned by the strtol(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.

       nptr    The  original  nptr,  exactly as	passed to the strtol(3)	system
	       call.

       endptr  The original endptr, exactly as passed to the strtol(3)	system
	       call.

       base    The  original  base,  exactly as	passed to the strtol(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:
	      long result = strtol(nptr, endptr, base);
	      if (result < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_strtol(err, nptr,
		  endptr, base));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_strtol
       void explain_message_strtol(char	*message, int message_size, const char
       *nptr, char **endptr, int base);

       The explain_message_strtol function is used to obtain an	explanation of
       an error	returned by the	strtol(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.

       nptr    The original nptr, exactly as passed to	the  strtol(3)	system
	       call.

       endptr  The  original endptr, exactly as	passed to the strtol(3)	system
	       call.

       base    The original base, exactly as passed to	the  strtol(3)	system
	       call.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      long result = strtol(nptr, endptr, base);
	      if (result < 0)
	      {
		  char message[3000];
		  explain_message_strtol(message, sizeof(message), nptr,
		  endptr, base);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_errno_strtol
       void explain_message_errno_strtol(char *message,	int message_size, int
       errnum, const char *nptr, char **endptr,	int base);

       The explain_message_errno_strtol	function is used to obtain an explana-
       tion of an error	returned by the	strtol(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.

       nptr    The  original  nptr,  exactly as	passed to the strtol(3)	system
	       call.

       endptr  The original endptr, exactly as passed to the strtol(3)	system
	       call.

       base    The  original  base,  exactly as	passed to the strtol(3)	system
	       call.

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

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

SEE ALSO
       strtol(3)
	       convert a string	to a long integer

       explain_strtol_or_die(3)
	       convert a string	to a long integer and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2009 Peter	Miller

							     explain_strtol(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=explain_strtol&sektion=3&manpath=FreeBSD+12.2-RELEASE+and+Ports>

home | help