.lf 1 ./man/man3/explain_rename.3 .\" .\" libexplain - Explain errno values returned by libc functions .\" Copyright (C) 2008, 2009 Peter Miller .\" Written by Peter Miller .\" .\" This program is free software; you can redistribute it and/or modify .\" it under the terms of the GNU General Public License as published by .\" the Free Software Foundation; either version 3 of the License, or .\" (at your option) any later version. .\" .\" This program is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU .\" General Public License for more details. .\" .\" You should have received a copy of the GNU General Public License .\" along with this program. If not, see . .\" .TH explain_rename 3 .SH NAME explain_rename \- explain rename(2) errors .if require_index \{ .\} .SH SYNOPSIS #include .br const char *explain_rename(const char *oldpath, const char *newpath); .br const char *explain_errno_rename(int errnum, const char *oldpath, const char *newpath); .br void explain_message_rename(char *message, int message_size, const char *oldpath, const char *newpath); .br void explain_message_errno_rename(char *message, int message_size, int errnum, const char *oldpath, const char *newpath); .SH DESCRIPTION The functions declared in the \f[CR]\fP include file may be used to explain errors returned by the \f[I]rename\fP(2) system call. .\" ------------------------------------------------------------------------ .SS explain_rename const char *explain_rename(const char *oldpath, const char *newpath); .PP The explain_rename function is used to obtain an explanation of an error returned by the \f[I]rename\fP(2) function. 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. .PP The \f[I]errno\fP global variable will be used to obtain the error value to be decoded. .PP This function is intended to be used in a fashion similar to the following example: .RS .ft CR .nf if (rename(oldpath, rewpath) < 0) { fprintf(stderr, "%s\en", explain_rename(oldpath, newpath)); exit(EXIT_FAILURE); } .ft R .fi .RE .TP 8n \f[I]oldpath\fP The original oldpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n \f[I]newpath\fP The original newpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n 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. .PP \f[B]Note:\fP This function is \f[B]not\fP thread safe, because it shares a return buffer across all threads, and many other functions in this library. .\" ------------------------------------------------------------------------ .SS explain_errno_rename const char *explain_errno_rename(int errnum, const char *oldpath, const char *newpath); .PP The explain_errno_rename function is used to obtain an explanation of an error returned by the rename(2) function. 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. .PP This function is intended to be used in a fashion similar to the following example: .RS .ft CR .nf if (rename(oldpath, newpath) < 0) { int err = errno; fprintf(stderr, "%s\en", explain_errno_rename(err, oldpath, newpath)); exit(EXIT_FAILURE); } .fi .ft R .RE .TP 8n \f[I]errnum\fP The error value to be decoded, usually obtained from the \f[I]errno\fP global variable just before this function is called. This is necessary if you need to call \f[B]any\fP code between the system call to be explained and this function, because many libc functions will alter the value of \f[I]errno\fP. .TP 8n \f[I]oldpath\fP The original oldpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n \f[I]newpath\fP The original newpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n 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. .PP \f[B]Note:\fP This function is \fBnot\fP thread safe, because it shares a return buffer across all threads, and many other functions in this library. .\" ------------------------------------------------------------------------ .SS explain_message_rename void explain_message_rename(char *message, int message_size, const char *oldpath, const char *newpath); .PP The explain_message_rename function is used to obtain an explanation of an error returned by the \f[I]rename\fP(2) function. 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. .PP The \f[I]errno\fP global variable will be used to obtain the error value to be decoded. .PP This function is intended to be used in a fashion similar to the following example: .RS .ft CR .nf if (rename(oldpath, newpath) < 0) { char message[3000]; explain_message_rename(message, sizeof(message), oldpath, newpath); fprintf(stderr, "%s\en", message); exit(EXIT_FAILURE); } .fi .ft R .RE .TP 8n \f[I]message\fP The location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe, if the buffer is thread safe. .TP 8n \f[I]message_size\fP The size in bytes of the location in which to store the returned message. .TP 8n \f[I]oldpath\fP The original oldpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n \fInewpath\fP The original newpath, exactly as passed to the \f[I]rename\fP(2) system call. .\" ------------------------------------------------------------------------ .SS explain_message_errno_rename void explain_message_errno_rename(char *message, int message_size, int errnum, const char *oldpath, const char *newpath); .PP The explain_message_errno_rename function is used to obtain an explanation of an error returned by the \f[I]rename\fP(2) function. 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. .PP This function is intended to be used in a fashion similar to the following example: .RS .ft CR .nf if (rename(oldpath, newpath) < 0) { int err = errno; char message[3000]; explain_message_errno_rename(message, sizeof(message), err, oldpath, newpath); fprintf(stderr, "%s\en", message); exit(EXIT_FAILURE); } .ft R .fi .RE .PP .TP 8n \f[I]message\fP The location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe, given a thread safe buffer. .TP 8n \f[I]message_size\fP The size in bytes of the location in which to store the returned message. .TP 8n \fIerrnum\fP The error value to be decoded, usually obtained from the \f[I]errno\fP global variable just before this function is called. This is necessary if you need to call \f[B]any\fP code between the system call to be explained and this function, because many libc functions will alter the value of \f[I]errno\fP. .TP 8n \f[I]oldpath\fP The original oldpath, exactly as passed to the \f[I]rename\fP(2) system call. .TP 8n \f[I]newpath\fP The original newpath, exactly as passed to the \f[I]rename\fP(2) system call. .\" ------------------------------------------------------------------------ .SH COPYRIGHT .lf 1 ./etc/version.so .ds v) 1.4 .ds V) 1.4.D001 .ds Y) 2008, 2009, 2010, 2011, 2012, 2013, 2014 .lf 226 ./man/man3/explain_rename.3 .if n .ds C) (C) .if t .ds C) \(co libexplain version \*(v) .br Copyright \*(C) 2008 Peter Miller .SH AUTHOR Written by Peter Miller