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explain_fchmod(3) Library Functions Manual explain_fchmod(3) NAME explain_fchmod - explain fchmod(2) errors SYNOPSIS #include <libexplain/fchmod.h> const char *explain_fchmod(int fildes, mode_t mode); const char *explain_errno_fchmod(int errnum, int fildes, mode_t mode); void explain_message_fchmod(char *message, int message_size, int fildes, mode_t mode); void explain_message_errno_fchmod(char *message, int message_size, int errnum, int fildes, mode_t mode); DESCRIPTION These functions may be used to obtain explanations for errors returned by the fchmod(2) system call. explain_fchmod const char *explain_fchmod(int fildes, mode_t mode); The explain_fchmod function is used to obtain an explanation of an er- ror returned by the fchmod(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. fildes The original fildes, exactly as passed to the fchmod(2) system call. mode The original mode, exactly as passed to the fchmod(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 (fchmod(fildes, mode) < 0) { fprintf(stderr, "%s\n", explain_fchmod(fildes, mode)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_fch- mod_or_die(3) function. explain_errno_fchmod const char *explain_errno_fchmod(int errnum, int fildes, mode_t mode); The explain_errno_fchmod function is used to obtain an explanation of an error returned by the fchmod(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 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. fildes The original fildes, exactly as passed to the fchmod(2) system call. mode The original mode, exactly as passed to the fchmod(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 (fchmod(fildes, mode) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_fchmod(err, fildes, mode)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_fch- mod_or_die(3) function. explain_message_fchmod void explain_message_fchmod(char *message, int message_size, int fildes, mode_t mode); The explain_message_fchmod function is used to obtain an explanation of an error returned by the fchmod(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 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. fildes The original fildes, exactly as passed to the fchmod(2) system call. mode The original mode, exactly as passed to the fchmod(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (fchmod(fildes, mode) < 0) { char message[3000]; explain_message_fchmod(message, sizeof(message), fildes, mode); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_fch- mod_or_die(3) function. explain_message_errno_fchmod void explain_message_errno_fchmod(char *message, int message_size, int errnum, int fildes, mode_t mode); The explain_message_errno_fchmod function is used to obtain an explana- tion of an error returned by the fchmod(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 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. fildes The original fildes, exactly as passed to the fchmod(2) system call. mode The original mode, exactly as passed to the fchmod(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (fchmod(fildes, mode) < 0) { int err = errno; char message[3000]; explain_message_errno_fchmod(message, sizeof(message), err, fildes, mode); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_fch- mod_or_die(3) function. SEE ALSO fchmod(2) change permissions of an open file explain_fchmod_or_die(3) change permissions of an open file and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2013 Peter Miller explain_fchmod(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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