explain_tmpnam(3)

💖 explain_tmpnam(3) 💖

okay so bestie, welcome to the libexplain corner of the Library Functions Manual 🫶 this whole page is about one lil' squad of functions whose entire job is explaining what went wrong with tmpnam(3). no cap.

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✨ NAME ✨

explain_tmpnam — bestie, this is the one that explains tmpnam(3) errors for you 💅

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🌸 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);

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💜 DESCRIPTION 💜

so like, these functions? they exist so you can get explanations for errors that the tmpnam(3) system call hands back to you. that's the whole vibe. 🌈

🎀 explain_tmpnam

const char *explain_tmpnam(char *pathname);

the explain_tmpnam function is your girl for getting an explanation of an error returned by the tmpnam(3) system call. the absolute bare minimum the message will contain is the value of strerror(errno), but honestly? usually it does so much better and points at the actual underlying cause in more detail. she's an overachiever, we love that. 👑

the errno global variable is the one that gets used to grab the error value that needs decoding.

• pathname — the original pathname, exactly as passed to the tmpnam(3) system call. like, character for character, no edits bestie.

Returns:

the message explaining the error. heads up though — this message buffer is shared by all libexplain functions that don't supply a buffer in their own argument list. so it will get overwritten by the very next call to any libexplain function sharing that buffer, including calls from other threads. 😭

Note: this function is not thread safe, because it shares a return buffer across all threads, and honestly across many other functions in this library too.

Example: this function is meant to be used in a fashion similar to this:

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. iykyk 💫

🦋 explain_errno_tmpnam

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

the explain_errno_tmpnam function gets you 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 does way more and tells you the underlying cause in more detail. periodt.

• errnum — the error value to be decoded, usually grabbed from the errno global variable right before this function is called. and why is that necessary? because if you need to run any code between the system call being explained and this function, bestie, many libc functions will change the value of errno out from under you. 🙈
• 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 that don't supply a buffer in their argument list. it gets overwritten by the next call to any libexplain function sharing this buffer, including other threads.

Note: not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example: meant to be used like this:

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 gets you 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 does much better and indicates the underlying cause in more detail. she ate. 💅

the errno global variable is used to obtain the error value to be decoded.

• message — the location in which to store the returned message. and here's the slay: 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: meant to be used like this:

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 gets you 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 does much better and indicates the underlying cause in more detail. iconic behaviour fr fr.

• 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: meant to be used like this:

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. ⭐

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👀 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

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📜 COPYRIGHT 📜

libexplain version 1.4 Copyright (C) 2010 Peter Miller

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and that's the whole page bestie, we're done!! 🎉 this was explain_tmpnam(3), straight out of the Library Functions Manual, brought to you by libexplain version 1.4, Copyright (C) 2010 Peter Miller — go forth and explain your errors, you absolute main character. 💖👑🦋