libexplain  1.4.D001
Functions
libexplain/lstat.h File Reference

explain lstat(2) errors More...

#include <libexplain/gcc_attributes.h>

Go to the source code of this file.

Functions

void explain_lstat_or_die (const char *pathname, struct stat *data)
int explain_lstat_on_error (const char *pathname, struct stat *data) LIBEXPLAIN_WARN_UNUSED_RESULT
const char * explain_lstat (const char *pathname, const struct stat *data) LIBEXPLAIN_WARN_UNUSED_RESULT
const char * explain_errno_lstat (int errnum, const char *pathname, const struct stat *data) LIBEXPLAIN_WARN_UNUSED_RESULT
void explain_message_lstat (char *message, int message_size, const char *pathname, const struct stat *data)
void explain_message_errno_lstat (char *message, int message_size, int errnum, const char *pathname, const struct stat *data)

Detailed Description

explain lstat(2) errors

Definition in file lstat.h.


Function Documentation

const char* explain_errno_lstat ( int  errnum,
const char *  pathname,
const struct stat *  data 
)

The explain_errno_lstat function is used to obtain an explanation of an error returned by the lstat(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 following example:

 if (lstat(pathname, data) < 0)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_lstat(err, pathname, data));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_lstat_or_die function.

Parameters:
errnumThe 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.
pathnameThe original pathname, exactly as passed to the lstat(2) system call.
dataThe original data, exactly as passed to the lstat(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.

Definition at line 25 of file lstat.c.

const char* explain_lstat ( const char *  pathname,
const struct stat *  data 
)

The explain_lstat function is used to obtain an explanation of an error returned by the lstat(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 following example:

 if (lstat(pathname, data) < 0)
 {
     fprintf(stderr, "%s\n", explain_lstat(pathname, data));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_lstat_or_die function.

Parameters:
pathnameThe original pathname, exactly as passed to the lstat(2) system call.
dataThe original data, exactly as passed to the lstat(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.

Definition at line 26 of file lstat.c.

int explain_lstat_on_error ( const char *  pathname,
struct stat *  data 
)

The explain_lstat_on_error function is used to call the lstat(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_lstat(3) function.

This function is intended to be used in a fashion similar to the following example:

 if (explain_lstat_on_error(pathname, data) < 0)
 {
     ...cope with error
     ...no need to print error message
 }
Parameters:
pathnameThe pathname, exactly as to be passed to the lstat(2) system call.
dataThe data, exactly as to be passed to the lstat(2) system call.
Returns:
The value returned by the wrapped lstat(2) system call.

Definition at line 27 of file lstat_on_error.c.

void explain_lstat_or_die ( const char *  pathname,
struct stat *  data 
)

The explain_lstat_or_die function is used to call the lstat(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_lstat(3) function, 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:

 explain_lstat_or_die(pathname, data);
Parameters:
pathnameThe pathname, exactly as to be passed to the lstat(2) system call.
dataThe data, exactly as to be passed to the lstat(2) system call.
Returns:
This function only returns on success. On failure, prints an explanation and exits, it does not return.

Definition at line 26 of file lstat_or_die.c.

void explain_message_errno_lstat ( char *  message,
int  message_size,
int  errnum,
const char *  pathname,
const struct stat *  data 
)

The explain_message_errno_lstat function is used to obtain an explanation of an error returned by the lstat(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 following example:

 if (lstat(pathname, data) < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_lstat(message, sizeof(message), err, pathname,
         data);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_lstat_or_die function.

Parameters:
messageThe location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_sizeThe size in bytes of the location in which to store the returned message.
errnumThe 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.
pathnameThe original pathname, exactly as passed to the lstat(2) system call.
dataThe original data, exactly as passed to the lstat(2) system call.

Definition at line 26 of file lstat.c.

void explain_message_lstat ( char *  message,
int  message_size,
const char *  pathname,
const struct stat *  data 
)

The explain_message_lstat function is used to obtain an explanation of an error returned by the lstat(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.

This function is intended to be used in a fashion similar to the following example:

 if (lstat(pathname, data) < 0)
 {
     char message[3000];
     explain_message_lstat(message, sizeof(message), pathname, data);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_lstat_or_die function.

Parameters:
messageThe location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_sizeThe size in bytes of the location in which to store the returned message.
pathnameThe original pathname, exactly as passed to the lstat(2) system call.
dataThe original data, exactly as passed to the lstat(2) system call.

Definition at line 26 of file lstat.c.