explain_munmap(3) Library Functions Manual explain_munmap(3)
NAME
explain_munmap - explain munmap(2) errors
SYNOPSIS
#include <libexplain/munmap.h>
const char *explain_munmap(void *data, size_t data_size);
const char *explain_errno_munmap(int errnum, void *data, size_t data_size);
void explain_message_munmap(char *message, int message_size, void *data, size_t data_size);
void explain_message_errno_munmap(char *message, int message_size, int errnum, void *data, size_t data_size);
DESCRIPTION
These functions may be used to obtain explanations for errors returned by the munmap(2) system call.
explain_munmap
const char *explain_munmap(void *data, size_t data_size);
The explain_munmap function is used to obtain an explanation of an error returned by the munmap(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.
data The original data, exactly as passed to the munmap(2) system call.
data_size
The original data_size, exactly as passed to the munmap(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:
if (munmap(data, data_size) < 0)
{
fprintf(stderr, "%s
", explain_munmap(data, data_size));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_munmap_or_die(3) function.
explain_errno_munmap
const char *explain_errno_munmap(int errnum, void *data, size_t data_size);
The explain_errno_munmap function is used to obtain an explanation of an error returned by the munmap(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.
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.
data The original data, exactly as passed to the munmap(2) system call.
data_size
The original data_size, exactly as passed to the munmap(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:
if (munmap(data, data_size) < 0)
{
int err = errno;
fprintf(stderr, "%s
", explain_errno_munmap(err, data, data_size));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_munmap_or_die(3) function.
explain_message_munmap
void explain_message_munmap(char *message, int message_size, void *data, size_t data_size);
The explain_message_munmap function is used to obtain an explanation of an error returned by the munmap(2) system call. 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.
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.
data The original data, exactly as passed to the munmap(2) system call.
data_size
The original data_size, exactly as passed to the munmap(2) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (munmap(data, data_size) < 0)
{
char message[3000];
explain_message_munmap(message, sizeof(message), data, data_size);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_munmap_or_die(3) function.
explain_message_errno_munmap
void explain_message_errno_munmap(char *message, int message_size, int errnum, void *data, size_t data_size);
The explain_message_errno_munmap function is used to obtain an explanation of an error returned by the munmap(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 explained and this function, because many libc functions will alter
the value of errno.
data The original data, exactly as passed to the munmap(2) system call.
data_size
The original data_size, exactly as passed to the munmap(2) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (munmap(data, data_size) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_munmap(message, sizeof(message), err, data, data_size);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_munmap_or_die(3) function.
SEE ALSO
munmap(2)
unmap a file or device from memory
explain_munmap_or_die(3)
unmap a file or device from memory and report errors
COPYRIGHT
libexplain version 0.52
Copyright (C) 2010 Peter Miller
explain_munmap(3)