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Functions |
const char * | explain_openat (int fildes, const char *pathname, int flags, mode_t mode) |
const char * | explain_errno_openat (int errnum, int fildes, const char *pathname, int flags, mode_t mode) |
void | explain_message_openat (char *message, int message_size, int fildes, const char *pathname, int flags, mode_t mode) |
void | explain_message_errno_openat (char *message, int message_size, int errnum, int fildes, const char *pathname, int flags, mode_t mode) |
Function Documentation
const char* explain_errno_openat |
( |
int |
errnum, |
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int |
fildes, |
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const char * |
pathname, |
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int |
flags, |
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mode_t |
mode |
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) |
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The explain_errno_openat function is used to obtain an explanation of an error returned by the openat(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.
- Parameters:
-
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 openat(2) system call. |
pathname | The original pathname, exactly as passed to the openat(2) system call. |
flags | The original flags, exactly as passed to the openat(2) system call. |
mode | The original mode, exactly as passed to the openat(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:
int result = openat(fildes, pathname, flags, mode);
if (result < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_openat(err, fildes, pathname,
flags, mode));
exit(EXIT_FAILURE);
}
- The above code example is available pre-packaged as the explain_openat_or_die function.
Definition at line 35 of file openat.c.
void explain_message_errno_openat |
( |
char * |
message, |
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int |
message_size, |
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int |
errnum, |
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int |
fildes, |
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const char * |
pathname, |
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int |
flags, |
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mode_t |
mode |
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) |
| |
The explain_message_errno_openat function is used to obtain an explanation of an error returned by the openat(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.
- Parameters:
-
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 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 openat(2) system call. |
pathname | The original pathname, exactly as passed to the openat(2) system call. |
flags | The original flags, exactly as passed to the openat(2) system call. |
mode | The original mode, exactly as passed to the openat(2) system call. |
- Example:
- This function is intended to be used in a fashion similar to the following example:
int result = openat(fildes, pathname, flags, mode);
if (result < 0)
{
int err = errno;
char message[3000];
explain_message_errno_openat(message, sizeof(message), err, fildes,
pathname, flags, mode);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
- The above code example is available pre-packaged as the explain_openat_or_die function.
Definition at line 55 of file openat.c.
void explain_message_openat |
( |
char * |
message, |
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|
int |
message_size, |
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int |
fildes, |
|
|
const char * |
pathname, |
|
|
int |
flags, |
|
|
mode_t |
mode |
|
) |
| |
The explain_message_openat function is used to obtain an explanation of an error returned by the openat(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.
The errno global variable will be used to obtain the error value to be decoded.
- Parameters:
-
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 openat(2) system call. |
pathname | The original pathname, exactly as passed to the openat(2) system call. |
flags | The original flags, exactly as passed to the openat(2) system call. |
mode | The original mode, exactly as passed to the openat(2) system call. |
- Example:
- This function is intended to be used in a fashion similar to the following example:
int result = openat(fildes, pathname, flags, mode);
if (result < 0)
{
char message[3000];
explain_message_openat(message, sizeof(message), fildes, pathname,
flags, mode);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
- The above code example is available pre-packaged as the explain_openat_or_die function.
Definition at line 46 of file openat.c.
const char* explain_openat |
( |
int |
fildes, |
|
|
const char * |
pathname, |
|
|
int |
flags, |
|
|
mode_t |
mode |
|
) |
| |
The explain_openat function is used to obtain an explanation of an error returned by the openat(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.
- Parameters:
-
fildes | The original fildes, exactly as passed to the openat(2) system call. |
pathname | The original pathname, exactly as passed to the openat(2) system call. |
flags | The original flags, exactly as passed to the openat(2) system call. |
mode | The original mode, exactly as passed to the openat(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:
- The above code example is available pre\-packaged as the explain_openat_or_die function.
Definition at line 28 of file openat.c.