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/*
* libexplain - Explain errno values returned by libc functions
* Copyright (C) 2010, 2013 Peter Miller
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful,but
* WITHOUT ANY WARRANTY; without even the implied warranty
* ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNULesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef LIBEXPLAIN_SETLINEBUF_H
#define LIBEXPLAIN_SETLINEBUF_H
/**
* @file
* @brief explain setlinebuf(3) errors
*
* These functions may be used to obtain explanations for errors returned
* by the <i>setlinebuf</i>(3) system call.
*/
#include <libexplain/gcc_attributes.h>
#include <libexplain/large_file_support.h>
#include <stdio.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* The explain_setlinebuf_or_die function is used to call the
* <i>setlinebuf</i>(3) system call. On failure an explanation will be
* printed to stderr, obtained from the <i>#explain_setlinebuf</i>(3)
* function, and then the process terminates by calling
* <tt>exit(EXIT_FAILURE)</tt>.
*
* @param fp
* The fp, exactly as to be passed to the <i>setlinebuf</i>(3) system
* call.
* @returns
* This function only returns on success, see <i>setlinebuf</i>(3) for
* more information. On failure, prints an explanation and exits, it
* does not return.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* explain_setlinebuf_or_die(fp);
* @endcode
*/
void explain_setlinebuf_or_die(FILE *fp);
/**
* The explain_setlinebuf_on_error function is used to call the
* <i>setlinebuf</i>(3) system call. On failure an explanation will be
* printed to stderr, obtained from the <i>#explain_setlinebuf</i>(3)
* function.
*
* @param fp
* The fp, exactly as to be passed to the <i>setlinebuf</i>(3) system
* call.
* @returns
* The value returned by the wrapped <i>setlinebuf</i>(3) system call.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* errno = 0;
* void result = explain_setlinebuf_on_error(fp);
* if (result < 0 && errno != 0)
* {
* ...cope with error
* ...no need to print error message
* }
* @endcode
*/
void explain_setlinebuf_on_error(FILE *fp);
/**
* The explain_setlinebuf function is used to obtain an explanation of an
* error returned by the <i>setlinebuf</i>(3) system call. The least the
* message will contain is the value of <tt>strerror(errno)</tt>, 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.
*
* @param fp
* The original fp, exactly as passed to the <i>setlinebuf</i>(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 <b>not</b> thread safe, because it shares a return
* buffer across all threads, and many other functions in this
* library.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* errno = 0;
* void result = setlinebuf(fp);
* if (result < 0 && errno != 0)
* {
* fprintf(stderr, "%s\n", explain_setlinebuf(fp));
* exit(EXIT_FAILURE);
* }
* @endcode
* @par
* The above code example is available pre-packaged as the
* #explain_setlinebuf_or_die function.
*/
const char *explain_setlinebuf(FILE *fp)
LIBEXPLAIN_WARN_UNUSED_RESULT;
/**
* The explain_errno_setlinebuf function is used to obtain an explanation
* of an error returned by the <i>setlinebuf</i>(3) system call. The least
* the message will contain is the value of <tt>strerror(errnum)</tt>, but
* usually it will do much better, and indicate the underlying cause in
* more detail.
*
* @param 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 <b>any</b> code between the system
* call to be explained and this function, because many libc functions
* will alter the value of errno.
* @param fp
* The original fp, exactly as passed to the <i>setlinebuf</i>(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 <b>not</b> thread safe, because it shares a return
* buffer across all threads, and many other functions in this
* library.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* errno = 0;
* void result = setlinebuf(fp);
* if (result < 0 && errno != 0)
* {
* int err = errno;
* fprintf(stderr, "%s\n", explain_errno_setlinebuf(err, fp));
* exit(EXIT_FAILURE);
* }
* @endcode
* @par
* The above code example is available pre-packaged as the
* #explain_setlinebuf_or_die function.
*/
const char *explain_errno_setlinebuf(int errnum, FILE *fp)
LIBEXPLAIN_WARN_UNUSED_RESULT;
/**
* The explain_message_setlinebuf function is used to obtain an
* explanation of an error returned by the <i>setlinebuf</i>(3) system
* call. The least the message will contain is the value of
* <tt>strerror(errnum)</tt>, 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.
*
* @param message
* The location in which to store the returned message. If a suitable
* message return buffer is supplied, this function is thread safe.
* @param message_size
* The size in bytes of the location in which to store the returned
* message.
* @param fp
* The original fp, exactly as passed to the <i>setlinebuf</i>(3)
* system call.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* errno = 0;
* void result = setlinebuf(fp);
* if (result < 0 && errno != 0)
* {
* char message[3000];
* explain_message_setlinebuf(message, sizeof(message), fp);
* fprintf(stderr, "%s\n", message);
* exit(EXIT_FAILURE);
* }
* @endcode
* @par
* The above code example is available pre-packaged as the
* #explain_setlinebuf_or_die function.
*/
void explain_message_setlinebuf(char *message, int message_size, FILE *fp);
/**
* The explain_message_errno_setlinebuf function is used to obtain an
* explanation of an error returned by the <i>setlinebuf</i>(3) system
* call. The least the message will contain is the value of
* <tt>strerror(errnum)</tt>, but usually it will do much better, and
* indicate the underlying cause in more detail.
*
* @param message
* The location in which to store the returned message. If a suitable
* message return buffer is supplied, this function is thread safe.
* @param message_size
* The size in bytes of the location in which to store the returned
* message.
* @param 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 <b>any</b> code between the system
* call to be explained and this function, because many libc functions
* will alter the value of errno.
* @param fp
* The original fp, exactly as passed to the <i>setlinebuf</i>(3)
* system call.
*
* @par Example:
* This function is intended to be used in a fashion similar to the
* following example:
* @code
* errno = 0;
* void result = setlinebuf(fp);
* if (result < 0 && errno != 0)
* {
* int err = errno;
* char message[3000];
* explain_message_errno_setlinebuf(message, sizeof(message), err, fp);
* fprintf(stderr, "%s\n", message);
* exit(EXIT_FAILURE);
* }
* @endcode
* @par
* The above code example is available pre-packaged as the
* #explain_setlinebuf_or_die function.
*/
void explain_message_errno_setlinebuf(char *message, int message_size, int
errnum, FILE *fp);
#ifdef __cplusplus
}
#endif
/* vim: set ts=8 sw=4 et : */
#endif /* LIBEXPLAIN_SETLINEBUF_H */
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