--- name: "explain_tmpfile" section: "3" platform: "linux" package: "libexplain-dev" version: "1.4.D001-16" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/explain_tmpfile" --- # explain\_tmpfile(3) explain tmpfile(3) errors ## NAME explain\_tmpfile - explain [*tmpfile*(3)](/tmpfile/3.md) errors ## SYNOPSIS \#include \ const char \*explain\_tmpfile(void);\ const char \*explain\_errno\_tmpfile(int errnum, void);\ void explain\_message\_tmpfile(char \*message, int message\_size, void);\ void explain\_message\_errno\_tmpfile(char \*message, int message\_size, int errnum, void); ## DESCRIPTION These functions may be used to obtain explanations for errors returned by the [*tmpfile*(3)](/tmpfile/3.md) system call. ### explain\_tmpfile const char \*explain\_tmpfile(void); The **explain\_tmpfile** function is used to obtain an explanation of an error returned by the [*tmpfile*(3)](/tmpfile/3.md) 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. - 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: `FILE *result = tmpfile();`\ `if (!result)` ``` { ``` `fprintf(stderr, "%s\n", explain_tmpfile());` ``` exit(EXIT_FAILURE); } ``` The above code example is available pre‐packaged as the [*explain\_tmpfile\_or\_die*(3)](/explain_tmpfile_or_die/3.md) function. ### explain\_errno\_tmpfile const char \*explain\_errno\_tmpfile(int errnum, void); The **explain\_errno\_tmpfile** function is used to obtain an explanation of an error returned by the [*tmpfile*(3)](/tmpfile/3.md) 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*. - 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: `FILE *result = tmpfile();`\ `if (!result)` ``` { int err = errno; ``` `fprintf(stderr, "%s\n", explain_errno_tmpfile(err, ));` ``` exit(EXIT_FAILURE); } ``` The above code example is available pre‐packaged as the [*explain\_tmpfile\_or\_die*(3)](/explain_tmpfile_or_die/3.md) function. ### explain\_message\_tmpfile void explain\_message\_tmpfile(char \*message, int message\_size, void); The **explain\_message\_tmpfile** function is used to obtain an explanation of an error returned by the [*tmpfile*(3)](/tmpfile/3.md) 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. **Example:** This function is intended to be used in a fashion similar to the following example: `FILE *result = tmpfile();`\ `if (!result)` ``` { char message[3000]; ``` `explain_message_tmpfile(message, sizeof(message), );` ``` fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } ``` The above code example is available pre‐packaged as the [*explain\_tmpfile\_or\_die*(3)](/explain_tmpfile_or_die/3.md) function. ### explain\_message\_errno\_tmpfile void explain\_message\_errno\_tmpfile(char \*message, int message\_size, int errnum, void); The **explain\_message\_errno\_tmpfile** function is used to obtain an explanation of an error returned by the [*tmpfile*(3)](/tmpfile/3.md) 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*. **Example:** This function is intended to be used in a fashion similar to the following example: `FILE *result = tmpfile();`\ `if (!result)` ``` { int err = errno; char message[3000]; ``` `explain_message_errno_tmpfile(message, sizeof(message), err, );` ``` fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } ``` The above code example is available pre‐packaged as the [*explain\_tmpfile\_or\_die*(3)](/explain_tmpfile_or_die/3.md) function. ## SEE ALSO - [*tmpfile*(3)](/tmpfile/3.md) create a temporary file - [*explain\_tmpfile\_or\_die*(3)](/explain_tmpfile_or_die/3.md) create a temporary file and report errors ## COPYRIGHT libexplain version 1.4\ Copyright (C) 2009 Peter Miller