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Diffstat (limited to 'lib/libelf/elf_errmsg.3')
-rw-r--r-- | lib/libelf/elf_errmsg.3 | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/lib/libelf/elf_errmsg.3 b/lib/libelf/elf_errmsg.3 new file mode 100644 index 0000000..f014168 --- /dev/null +++ b/lib/libelf/elf_errmsg.3 @@ -0,0 +1,107 @@ +.\" Copyright (c) 2006 Joseph Koshy. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" This software is provided by Joseph Koshy ``as is'' and +.\" any express or implied warranties, including, but not limited to, the +.\" implied warranties of merchantability and fitness for a particular purpose +.\" are disclaimed. in no event shall Joseph Koshy be liable +.\" for any direct, indirect, incidental, special, exemplary, or consequential +.\" damages (including, but not limited to, procurement of substitute goods +.\" or services; loss of use, data, or profits; or business interruption) +.\" however caused and on any theory of liability, whether in contract, strict +.\" liability, or tort (including negligence or otherwise) arising in any way +.\" out of the use of this software, even if advised of the possibility of +.\" such damage. +.\" +.\" $FreeBSD$ +.\" +.Dd June 11, 2006 +.Dt ELF_ERRMSG 3 +.Os +.Sh NAME +.Nm elf_errmsg , +.Nm elf_errno +.Nd ELF library error message handling +.Sh LIBRARY +.Lb libelf +.Sh SYNOPSIS +.In libelf.h +.Ft int +.Fn elf_errno "void" +.Ft "const char *" +.Fn elf_errmsg "int error" +.Sh DESCRIPTION +When an error occurs during an ELF library API call, the library +encodes the error using an error number and stores the error number +internally for retrieval by the application at a later point of time. +Error numbers may contain an OS supplied error code in addition to +an ELF API specific error code. +An error number value of zero indicates no error. +.Pp +Function +.Fn elf_errno +is used to retrieve the last error recorded by the ELF library. +Invoking this function has the side-effect of resetting the +ELF library's recorded error number to zero. +.Pp +The function +.Fn elf_errmsg +returns a null-terminated string with a human readable +description of the error specified in argument +.Ar error . +A zero value for argument +.Ar error +retrieves the most recent error encountered by the ELF +library. +An argument value of -1 behaves identically, except that +it guarantees a non-NULL return from +.Fn elf_errmsg . +.Sh RETURN VALUES +Function +.Fn elf_errno +returns a non-zero value encoding the last error encountered +by the ELF library, or zero if no error was encountered. +.Pp +Function +.Fn elf_errmsg +returns a pointer to library local storage for non-zero values +of argument +.Ar error . +With a zero argument, the function will return a NULL pointer if no +error had been encountered by the library, or will return a pointer to +library local storage containing an appropriate message otherwise. +.Sh EXAMPLES +Clearing the ELF library's recorded error number can be accomplished +by invoking +.Fn elf_errno +and discarding its return value. +.Bd -literal -offset indent +/* clear error */ +(void) elf_errno(); +.Ed +.Pp +Retrieving a human-readable description of the current error number +can be done with the following snippet: +.Bd -literal -offset indent +int err; +const char *errmsg; +\&... +err = elf_errno(); +if (err != 0) + errmsg = elf_errmsg(err); +.Ed +.Sh SEE ALSO +.Xr elf 3 , +.Xr gelf 3 +.Sh BUGS +Function +.Fn elf_errmsg +is not localized. |