explain_tmpnam man page

explain_tmpnam — explain tmpnam(3) errors

Synopsis

#include <libexplain/tmpnam.h>

const char *explain_tmpnam(char *pathname);
const char *explain_errno_tmpnam(int errnum, char *pathname);
void explain_message_tmpnam(char *message, int message_size, char *pathname);
void explain_message_errno_tmpnam(char *message, int message_size, int errnum, char *pathname);

Description

These functions may be used to obtain explanations for errors returned by the tmpnam(3) system call.

explain_tmpnam

const char *explain_tmpnam(char *pathname);

The explain_tmpnam function is used to obtain an explanation of an error returned by the tmpnam(3) 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.

pathname
The original pathname, exactly as passed to the tmpnam(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.

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

char *result = tmpnam(pathname);
if (!result)

{

fprintf(stderr, "%s\n", explain_tmpnam(pathname));

    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_tmpnam_or_die(3) function.

explain_errno_tmpnam

const char *explain_errno_tmpnam(int errnum, char *pathname);

The explain_errno_tmpnam function is used to obtain an explanation of an error returned by the tmpnam(3) 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 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.
pathname
The original pathname, exactly as passed to the tmpnam(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.

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

char *result = tmpnam(pathname);
if (!result)

{
    int err = errno;

fprintf(stderr, "%s\n", explain_errno_tmpnam(err, pathname));

    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_tmpnam_or_die(3) function.

explain_message_tmpnam

void explain_message_tmpnam(char *message, int message_size, char *pathname);

The explain_message_tmpnam function is used to obtain an explanation of an error returned by the tmpnam(3) 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.

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.
pathname
The original pathname, exactly as passed to the tmpnam(3) system call.

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

char *result = tmpnam(pathname);
if (!result)

{
    char message[3000];

explain_message_tmpnam(message, sizeof(message), pathname);

    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_tmpnam_or_die(3) function.

explain_message_errno_tmpnam

void explain_message_errno_tmpnam(char *message, int message_size, int errnum, char *pathname);

The explain_message_errno_tmpnam function is used to obtain an explanation of an error returned by the tmpnam(3) 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 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.
pathname
The original pathname, exactly as passed to the tmpnam(3) system call.

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

char *result = tmpnam(pathname);
if (!result)

{
    int err = errno;
    char message[3000];

explain_message_errno_tmpnam(message, sizeof(message), err, pathname);

    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

The above code example is available pre‐packaged as the explain_tmpnam_or_die(3) function.

See Also

tmpnam(3)
create a name for a temporary file
explain_tmpnam_or_die(3)
create a name for a temporary file and report errors

Referenced By

explain(3), explain_tmpnam_or_die(3).