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explain_socket(3) Library Functions Manual explain_socket(3) NAME explain_socket - explain socket(2) errors SYNOPSIS #include <libexplain/socket.h> const char *explain_socket(int domain, int type, int protocol); const char *explain_errno_socket(int errnum, int domain, int type, int protocol); void explain_message_socket(char *message, int message_size, int do- main, int type, int protocol); void explain_message_errno_socket(char *message, int message_size, int errnum, int domain, int type, int protocol); DESCRIPTION These functions may be used to obtain explanations for errors returned by the socket(2) system call. explain_socket const char *explain_socket(int domain, int type, int protocol); The explain_socket function is used to obtain an explanation of an er- ror returned by the socket(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 fol- lowing example: if (socket(domain, type, protocol) < 0) { fprintf(stderr, "%s\n", explain_socket(domain, type, protocol)); exit(EXIT_FAILURE); } domain The original domain, exactly as passed to the socket(2) system call. type The original type, exactly as passed to the socket(2) system call. protocol The original protocol, exactly as passed to the socket(2) sys- tem 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, in- cluding 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_socket const char *explain_errno_socket(int errnum, int domain, int type, int protocol); The explain_errno_socket function is used to obtain an explanation of an error returned by the socket(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 fol- lowing example: if (socket(domain, type, protocol) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_socket(err, domain, type, protocol)); 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. domain The original domain, exactly as passed to the socket(2) system call. type The original type, exactly as passed to the socket(2) system call. protocol The original protocol, exactly as passed to the socket(2) sys- tem 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, in- cluding 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_socket void explain_message_socket(char *message, int message_size, int do- main, int type, int protocol); The explain_message_socket function may be used to obtain an explana- tion of an error returned by the socket(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 fol- lowing example: if (socket(domain, type, protocol) < 0) { char message[3000]; explain_message_socket(message, sizeof(message), domain, type, protocol); 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 re- turned message. domain The original domain, exactly as passed to the socket(2) system call. type The original type, exactly as passed to the socket(2) system call. protocol The original protocol, exactly as passed to the socket(2) sys- tem call. explain_message_errno_socket void explain_message_errno_socket(char *message, int message_size, int errnum, int domain, int type, int protocol); The explain_message_errno_socket function may be used to obtain an ex- planation of an error returned by the socket(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 de- tail. This function is intended to be used in a fashion similar to the fol- lowing example: if (socket(domain, type, protocol) < 0) { int err = errno; char message[3000]; explain_message_errno_socket(message, sizeof(message), err, domain, type, protocol); 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 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. domain The original domain, exactly as passed to the socket(2) system call. type The original type, exactly as passed to the socket(2) system call. protocol The original protocol, exactly as passed to the socket(2) sys- tem call. SEE ALSO socket(2) create an endpoint for communication explain_socket_or_die(3) create an endpoint for communication and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2008 Peter Miller explain_socket(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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