explain_setdomainname_or_die(3) [debian man page]
explain_setdomainname_or_die(3) Library Functions Manual explain_setdomainname_or_die(3) NAME
explain_setdomainname_or_die - set domain name and report errors SYNOPSIS
#include <libexplain/setdomainname.h> void explain_setdomainname_or_die(const char *data, size_t data_size); int explain_setdomainname_on_error(const char *data, size_t data_size); DESCRIPTION
The explain_setdomainname_or_die function is used to call the setdomainname(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_setdomainname(3) function, and then the process terminates by calling exit(EXIT_FAILURE). The explain_setdomainname_on_error function is used to call the setdomainname(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_setdomainname(3) function, but still returns to the caller. data The data, exactly as to be passed to the setdomainname(2) system call. data_size The data_size, exactly as to be passed to the setdomainname(2) system call. RETURN VALUE
The explain_setdomainname_or_die function only returns on success, see setdomainname(2) for more information. On failure, prints an expla- nation and exits, it does not return. The explain_setdomainname_on_error function always returns the value return by the wrapped setdomainname(2) system call. EXAMPLE
The explain_setdomainname_or_die function is intended to be used in a fashion similar to the following example: explain_setdomainname_or_die(data, data_size); SEE ALSO
setdomainname(2) set domain name explain_setdomainname(3) explain setdomainname(2) errors exit(2) terminate the calling process COPYRIGHT
libexplain version 0.52 Copyright (C) 2009 Peter Miller explain_setdomainname_or_die(3)
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explain_setdomainname(3) Library Functions Manual explain_setdomainname(3) NAME
explain_setdomainname - explain setdomainname(2) errors SYNOPSIS
#include <libexplain/setdomainname.h> const char *explain_setdomainname(const char *data, size_t data_size); const char *explain_errno_setdomainname(int errnum, const char *data, size_t data_size); void explain_message_setdomainname(char *message, int message_size, const char *data, size_t data_size); void explain_message_errno_setdomainname(char *message, int message_size, int errnum, const char *data, size_t data_size); DESCRIPTION
These functions may be used to obtain explanations for errors returned by the setdomainname(2) system call. explain_setdomainname const char *explain_setdomainname(const char *data, size_t data_size); The explain_setdomainname function is used to obtain an explanation of an error returned by the setdomainname(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. data The original data, exactly as passed to the setdomainname(2) system call. data_size The original data_size, exactly as passed to the setdomainname(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. Example: This function is intended to be used in a fashion similar to the following example: if (setdomainname(data, data_size) < 0) { fprintf(stderr, "%s ", explain_setdomainname(data, data_size)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_setdomainname_or_die(3) function. explain_errno_setdomainname const char *explain_errno_setdomainname(int errnum, const char *data, size_t data_size); The explain_errno_setdomainname function is used to obtain an explanation of an error returned by the setdomainname(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. errnum The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is neces- sary 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. data The original data, exactly as passed to the setdomainname(2) system call. data_size The original data_size, exactly as passed to the setdomainname(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. Example: This function is intended to be used in a fashion similar to the following example: if (setdomainname(data, data_size) < 0) { int err = errno; fprintf(stderr, "%s ", explain_errno_setdomainname(err, data, data_size)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_setdomainname_or_die(3) function. explain_message_setdomainname void explain_message_setdomainname(char *message, int message_size, const char *data, size_t data_size); The explain_message_setdomainname function is used to obtain an explanation of an error returned by the setdomainname(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. 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. data The original data, exactly as passed to the setdomainname(2) system call. data_size The original data_size, exactly as passed to the setdomainname(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (setdomainname(data, data_size) < 0) { char message[3000]; explain_message_setdomainname(message, sizeof(message), data, data_size); fprintf(stderr, "%s ", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_setdomainname_or_die(3) function. explain_message_errno_setdomainname void explain_message_errno_setdomainname(char *message, int message_size, int errnum, const char *data, size_t data_size); The explain_message_errno_setdomainname function is used to obtain an explanation of an error returned by the setdomainname(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. 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 neces- sary 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. data The original data, exactly as passed to the setdomainname(2) system call. data_size The original data_size, exactly as passed to the setdomainname(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (setdomainname(data, data_size) < 0) { int err = errno; char message[3000]; explain_message_errno_setdomainname(message, sizeof(message), err, data, data_size); fprintf(stderr, "%s ", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_setdomainname_or_die(3) function. SEE ALSO
setdomainname(2) set domain name explain_setdomainname_or_die(3) set domain name and report errors COPYRIGHT
libexplain version 0.52 Copyright (C) 2009 Peter Miller explain_setdomainname(3)