explain_flock(3) Library Functions Manual explain_flock(3) NAME explain_flock - explain flock(2) errors SYNOPSIS #include <libexplain/flock.h> const char *explain_flock(int fildes, int command); const char *explain_errno_flock(int errnum, int fildes, int command); void explain_message_flock(char *message, int message_size, int fildes, int command); void explain_message_errno_flock(char *message, int message_size, int er- rnum, int fildes, int command); DESCRIPTION These functions may be used to obtain explanations for errors returned by the flock(2) system call. explain_flock const char *explain_flock(int fildes, int command); The explain_flock function is used to obtain an explanation of an error re- turned by the flock(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indi- cate the underlying cause in more detail. The errno global variable will be used to obtain the error value to be de- coded. fildes The original fildes, exactly as passed to the flock(2) system call. command The original command, exactly as passed to the flock(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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 (flock(fildes, command) < 0) { fprintf(stderr, "%s\n", explain_flock(fildes, command)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the ex- plain_flock_or_die(3) function. explain_errno_flock const char *explain_errno_flock(int errnum, int fildes, int command); The explain_errno_flock function is used to obtain an explanation of an er- ror returned by the flock(2) system call. The least the message will con- tain 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 ex- plained and this function, because many libc functions will alter the value of errno. fildes The original fildes, exactly as passed to the flock(2) system call. command The original command, exactly as passed to the flock(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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 (flock(fildes, command) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_flock(err, fildes, com- mand)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the ex- plain_flock_or_die(3) function. explain_message_flock void explain_message_flock(char *message, int message_size, int fildes, int command); The explain_message_flock function is used to obtain an explanation of an error returned by the flock(2) system call. The least the message will con- tain 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 de- coded. 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. fildes The original fildes, exactly as passed to the flock(2) system call. command The original command, exactly as passed to the flock(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (flock(fildes, command) < 0) { char message[3000]; explain_message_flock(message, sizeof(message), fildes, com- mand); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the ex- plain_flock_or_die(3) function. explain_message_errno_flock void explain_message_errno_flock(char *message, int message_size, int er- rnum, int fildes, int command); The explain_message_errno_flock function is used to obtain an explanation of an error returned by the flock(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 ex- plained and this function, because many libc functions will alter the value of errno. fildes The original fildes, exactly as passed to the flock(2) system call. command The original command, exactly as passed to the flock(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (flock(fildes, command) < 0) { int err = errno; char message[3000]; explain_message_errno_flock(message, sizeof(message), err, fildes, command); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the ex- plain_flock_or_die(3) function. SEE ALSO flock(2) apply or remove an advisory lock on an open file explain_flock_or_die(3) apply or remove an advisory lock on an open file and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2009 Peter Miller explain_flock(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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