explain_opendir_or_die(3) [debian man page]
explain_opendir_or_die(3) Library Functions Manual explain_opendir_or_die(3) NAME
explain_opendir_or_die - open a directory and report errors SYNOPSIS
#include <libexplain/opendir.h> DIR *explain_opendir_or_die(const char *pathname); DESCRIPTION
The explain_opendir_or_die function is used to call the opendir(3) system call. On failure an explanation will be printed to stderr, obtained from explain_opendir(3), and then the process terminates by calling exit(EXIT_FAILURE). This function is intended to be used in a fashion similar to the following example: DIR *dir = explain_opendir_or_die(pathname); pathname The pathname, exactly as to be passed to the opendir(3) system call. Returns: On success, a pointer to the directory stream. On failure, prints an explanation and exits, does not return. SEE ALSO
opendir(3) open a directory explain_opendir(3) explain opendir(3) errors exit(2) terminate the calling process COPYRIGHT
libexplain version 0.52 Copyright (C) 2008 Peter Miller explain_opendir_or_die(3)
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explain_opendir(3) Library Functions Manual explain_opendir(3) NAME
explain_opendir - explain opendir(3) errors SYNOPSIS
const char *explain_opendir(const char *pathname); const char *explain_errno_opendir(int errnum, const char *pathname); int errnum, const char *pathname); void explain_message_opendir(char *message, int message_size, void explain_message_errno_opendir(char *message, int message_size, const char *pathname); DESCRIPTION
These functions may be used to explain opendir(3) errors. explain_opendir const char *explain_opendir(const char *pathname); The explain_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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 following example: DIR *dp = opendir(pathname); if (!dp) { fprintf(stderr, "%s ", explain_opendir(pathname)); exit(EXIT_FAILURE); } pathname The original pathname, exactly as passed to the opendir(3) 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. explain_errno_opendir const char *explain_errno_opendir(int errnum, const char *pathname); int errnum, const char *pathname); The explain_errno_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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 following example: DIR *dp = opendir(pathname); if (!dp) { int errnum = errno; const char *message = explain_errno_opendir(errnum, pathname); fprintf(stderr, "%s ", message); 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 neces- sary 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. pathname The original pathname, exactly as passed to the opendir(3) 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. explain_message_opendir void explain_message_opendir(char *message, int message_size, const char *pathname); The explain_message_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. The least the mes- sage 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 following example: DIR *dp = opendir(pathname); if (!dp) { char message[3000]; explain_message_opendir(message, sizeof(message), pathname); fprintf(stderr, "%s ", message); exit(EXIT_FAILURE); } message The location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe if the buffer is thread safe. message_size The size in bytes of the location in which to store the returned message. pathname The original pathname, exactly as passed to the opendir(3) system call. explain_message_errno_opendir void explain_message_errno_opendir(char *message, int message_size, const char *pathname); The explain_message_errno_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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 following example: DIR *dp = opendir(pathname); if (!dp); { int err = errno; char message[3000]; explain_message_errno_opendir(message, sizeof(message), err, pathname); fprintf(stderr, '%s ', message); exit(EXIT_FAILURE); } message The location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe if the buffer 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 explained and this function, because many libc functions will alter the value of errno. pathname The original pathname, exactly as passed to the opendir(3) system call. COPYRIGHT
libexplain version 0.52 Copyright (C) 2008 Peter Miller AUTHOR
Written by Peter Miller <pmiller@opensource.org.au> explain_opendir(3)