explain_getresgid(3) Library Functions Manual explain_getresgid(3) NAME explain_getresgid - explain getresgid(2) errors SYNOPSIS #include <libexplain/getresgid.h> const char *explain_getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid); const char *explain_errno_getresgid(int errnum, gid_t *rgid, gid_t *egid, gid_t *sgid); void explain_message_getresgid(char *message, int message_size, gid_t *rgid, gid_t *egid, gid_t *sgid); void explain_message_errno_getresgid(char *message, int message_size, int errnum, gid_t *rgid, gid_t *egid, gid_t *sgid); DESCRIPTION These functions may be used to obtain explanations for errors returned by the getresgid(2) system call. explain_getresgid const char *explain_getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid); The explain_getresgid function is used to obtain an explanation of an error returned by the getresgid(2) system call. The least the message will con- tain 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 de- coded. rgid The original rgid, exactly as passed to the getresgid(2) system call. egid The original egid, exactly as passed to the getresgid(2) system call. sgid The original sgid, exactly as passed to the getresgid(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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 (getresgid(rgid, egid, sgid) < 0) { fprintf(stderr, "%s\n", explain_getresgid(rgid, egid, sgid)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getres- gid_or_die(3) function. explain_errno_getresgid const char *explain_errno_getresgid(int errnum, gid_t *rgid, gid_t *egid, gid_t *sgid); The explain_errno_getresgid function is used to obtain an explanation of an error returned by the getresgid(2) system call. The least the message will contain is the value of strerror(errno), but usually it will do much bet- ter, 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 ex- plained and this function, because many libc functions will alter the value of errno. rgid The original rgid, exactly as passed to the getresgid(2) system call. egid The original egid, exactly as passed to the getresgid(2) system call. sgid The original sgid, exactly as passed to the getresgid(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 ar- gument list. This will be overwritten by the next call to any lib- explain 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 (getresgid(rgid, egid, sgid) < 0) { int err = errno; fprintf(stderr, "%s\n", explain_errno_getresgid(err, rgid, egid, sgid)); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getres- gid_or_die(3) function. explain_message_getresgid void explain_message_getresgid(char *message, int message_size, gid_t *rgid, gid_t *egid, gid_t *sgid); The explain_message_getresgid function is used to obtain an explanation of an error returned by the getresgid(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 de- coded. 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. rgid The original rgid, exactly as passed to the getresgid(2) system call. egid The original egid, exactly as passed to the getresgid(2) system call. sgid The original sgid, exactly as passed to the getresgid(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (getresgid(rgid, egid, sgid) < 0) { char message[3000]; explain_message_getresgid(message, sizeof(message), rgid, egid, sgid); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getres- gid_or_die(3) function. explain_message_errno_getresgid void explain_message_errno_getresgid(char *message, int message_size, int errnum, gid_t *rgid, gid_t *egid, gid_t *sgid); The explain_message_errno_getresgid function is used to obtain an explana- tion of an error returned by the getresgid(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 ex- plained and this function, because many libc functions will alter the value of errno. rgid The original rgid, exactly as passed to the getresgid(2) system call. egid The original egid, exactly as passed to the getresgid(2) system call. sgid The original sgid, exactly as passed to the getresgid(2) system call. Example: This function is intended to be used in a fashion similar to the following example: if (getresgid(rgid, egid, sgid) < 0) { int err = errno; char message[3000]; explain_message_errno_getresgid(message, sizeof(message), err, rgid, egid, sgid); fprintf(stderr, "%s\n", message); exit(EXIT_FAILURE); } The above code example is available pre-packaged as the explain_getres- gid_or_die(3) function. SEE ALSO getresgid(2) get real, effective and saved group IDs explain_getresgid_or_die(3) get real, effective and saved group IDs and report errors COPYRIGHT libexplain version 1.3 Copyright (C) 2012 Peter Miller explain_getresgid(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT
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