FreeBSD Manual Pages
explain_fstat(3) Library Functions Manual explain_fstat(3) NAME explain_fstat - explain fstat(2) errors SYNOPSIS #include <libexplain/fstat.h> const char *explain_fstat(int fildes, struct stat *buf); const char *explain_errno_fstat(int errnum, int fildes, struct stat *buf); void explain_message_fstat(char *message, int message_size, int fildes, struct stat *buf); void explain_message_errno_fstat(char *message, int message_size, int errnum, int fildes, struct stat *buf); DESCRIPTION These functions may be used to obtain explanations for errors returned by the fstat(2) system call. explain_fstat const char *explain_fstat(int fildes, struct stat *buf); The explain_fstat function is used to obtain an explanation of an error returned by the fstat(2) system call. The least the message will con- tain is the value of strerror(errno), but usually it will do much bet- ter, 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 (fstat(fildes, buf) < 0) { fprintf(stderr, "%s\n", explain_fstat(fildes, buf)); exit(EXIT_FAILURE); } fildes The original fildes, exactly as passed to the fstat(2) system call. buf The original buf, exactly as passed to the fstat(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, 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_fstat const char *explain_errno_fstat(int errnum, int fildes, struct stat *buf); The explain_errno_fstat function is used to obtain an explanation of an error returned by the fstat(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 (fstat(fildes, buf) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_fstat(err, fildes, buf)); 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. fildes The original fildes, exactly as passed to the fstat(2) system call. buf The original buf, exactly as passed to the fstat(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, 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_fstat void explain_message_fstat(char *message, int message_size, int fildes, struct stat *buf); The explain_message_fstat function may be used to obtain an explana- tion of an error returned by the fstat(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 (fstat(fildes, buf) < 0) { char message[3000]; explain_message_fstat(message, sizeof(message), fildes, buf); 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. fildes The original fildes, exactly as passed to the fstat(2) system call. buf The original buf, exactly as passed to the fstat(2) system call. explain_message_errno_fstat void explain_message_errno_fstat(char *message, int message_size, int errnum, int fildes, struct stat *buf); The explain_message_errno_fstat function may be used to obtain an ex- planation of an error returned by the fstat(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 (fstat(fildes, buf) < 0) { int err = errno; char message[3000]; explain_message_errno_fstat(message, sizeof(message), err, fildes, buf); 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. fildes The original fildes, exactly as passed to the fstat(2) system call. buf The original buf, exactly as passed to the fstat(2) system call. SEE ALSO fstat(2) get file status explain_fstat_or_die(3) get file status and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2008 Peter Miller explain_fstat(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=explain_fstat&sektion=3&manpath=FreeBSD+Ports+15.0.quarterly>