FreeBSD Manual Pages
explain_ftruncate(3) Library Functions Manual explain_ftruncate(3) NAME explain_ftruncate - explain ftruncate(2) errors SYNOPSIS #include <libexplain/ftruncate.h> const char *explain_ftruncate(int fildes, long long length); const char *explain_errno_ftruncate(int errnum, int fildes, long long length); void explain_message_ftruncate(char *message, int message_size, int fildes, long long length); void explain_message_errno_ftruncate(char *message, int message_size, int errnum, int fildes, long long length); DESCRIPTION These functions may be used to obtain explanations for errors returned by the ftruncate(2) system call. explain_ftruncate const char *explain_ftruncate(int fildes, long long length); The explain_ftruncate function is used to obtain an explanation of an error returned by the ftruncate(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 (ftruncate(fildes, length) < 0) { fprintf(stderr, "%s\n", explain_ftruncate(fildes, length)); exit(EXIT_FAILURE); } fildes The original fildes, exactly as passed to the ftruncate(2) sys- tem call. length The original length, exactly as passed to the ftruncate(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_ftruncate const char *explain_errno_ftruncate(int errnum, int fildes, long long length); The explain_errno_ftruncate function is used to obtain an explanation of an error returned by the ftruncate(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 (ftruncate(fildes, length) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_ftruncate(err, fildes, length)); 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 ftruncate(2) sys- tem call. length The original length, exactly as passed to the ftruncate(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_ftruncate void explain_message_ftruncate(char *message, int message_size, int fildes, long long length); The explain_message_ftruncate function may be used to obtain an expla- nation of an error returned by the ftruncate(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 de- tail. 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 (ftruncate(fildes, length) < 0) { char message[3000]; explain_message_ftruncate(message, sizeof(message), fildes, length); 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 ftruncate(2) sys- tem call. length The original length, exactly as passed to the ftruncate(2) sys- tem call. explain_message_errno_ftruncate void explain_message_errno_ftruncate(char *message, int message_size, int errnum, int fildes, long long length); The explain_message_errno_ftruncate function may be used to obtain an explanation of an error returned by the ftruncate(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 (ftruncate(fildes, length) < 0) { int err = errno; char message[3000]; explain_message_errno_ftruncate(message, sizeof(message), err, fildes, length); 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 ftruncate(2) sys- tem call. length The original length, exactly as passed to the ftruncate(2) sys- tem call. SEE ALSO ftruncate(2) truncate a file to a specified length explain_ftruncate_or_die(3) truncate a file and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2008 Peter Miller explain_ftruncate(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_ftruncate&sektion=3&manpath=FreeBSD+Ports+15.0.quarterly>