--- name: "explain_unlink" section: "3" platform: "linux" package: "libexplain-dev" version: "1.4.D001-16" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/explain_unlink" --- # explain\_unlink(3) explain unlink(2) errors ## NAME explain\_unlink - explain [unlink(2)](/unlink/2.md) errors ## SYNOPSIS \#include \\ const char \*explain\_unlink(const char \*pathname);\ void explain\_message\_unlink(char \*message, int message\_size, const char \*pathname);\ const char \*explain\_errno\_unlink(int errnum, const char \*pathname);\ void explain\_message\_errno\_unlink(char \*message, int message\_size, int errnum, const char \*pathname); ## DESCRIPTION These functions may be used to obtain explanations for [*unlink*(2)](/unlink/2.md) errors. ### explain\_unlink const char \*explain\_unlink(const char \*pathname); The explain\_unlink function is used to obtain an explanation of an error returned by the [*unlink*(2)](/unlink/2.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. This function is intended to be used in a fashion similar to the following example: ``` if (unlink(pathname) < 0) { fprintf(stderr, '%s0, explain_unlink(pathname)); exit(EXIT_FAILURE); } ``` - *pathname* The original pathname, exactly as passed to the [*unlink*(2)](/unlink/2.md) 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. ### explain\_errno\_unlink const char \*explain\_errno\_unlink(int errnum, const char \* pathname); The explain\_errno\_unlink function is used to obtain an explanation of an error returned by the [*unlink*(2)](/unlink/2.md) 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 (unlink(pathname) < 0) { int err = errno; fprintf(stderr, '%s0, explain_errno_unlink(err, pathname)); exit(EXIT_FAILURE); } ``` - *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 [*unlink*(2)](/unlink/2.md) 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. ### explain\_message\_unlink void explain\_message\_unlink(char \*message, int message\_size, const char \*pathname); The explain\_message\_unlink function is used to obtain an explanation of an error returned by the [*unlink*(2)](/unlink/2.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. This function is intended to be used in a fashion similar to the following example: ``` if (unlink(pathname) < 0) { char message[3000]; explain_message_unlink(message, sizeof(message), pathname); fprintf(stderr, '%s0, message); exit(EXIT_FAILURE); } ``` - *message* The location in which to store the returned message. Because a message return buffer has been 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 [*unlink*(2)](/unlink/2.md) system call. ### explain\_message\_errno\_unlink void explain\_message\_errno\_unlink(char \*message, int message\_size, int errnum, const char \*pathname); The explain\_message\_errno\_unlink function is used to obtain an explanation of an error returned by the [*unlink*(2)](/unlink/2.md) 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 (unlink(pathname) < 0) { int err = errno; char message[3000]; explain_message_errno_unlink(message, sizeof(message), err, pathname); fprintf(stderr, '%s0, message); exit(EXIT_FAILURE); } ``` - *message* The location in which to store the returned message. Because a message return buffer has been 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 [*unlink*(2)](/unlink/2.md) system call. ## COPYRIGHT libexplain version 1.4\ Copyright (C) 2008 Peter Miller ## AUTHOR Written by Peter Miller \