Manual Pages  — ELF_ERRMSG

elf_errmsg, elf_errno – ELF library error message handling

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES EXAMPLES SEE ALSO BUGS

ELF Access Library (libelf, -lelf)

#include <libelf.h>

int
elf_errno(void);

const char *
elf_errmsg(int error);

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.

Function 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.

The function elf_errmsg() returns a null-terminated string with a human readable description of the error specified in argument error. A zero value for argument 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 elf_errmsg().

Function elf_errno() returns a non-zero value encoding the last error encountered by the ELF library, or zero if no error was encountered.

Function elf_errmsg() returns a pointer to library local storage for non-zero values of argument 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.

Clearing the ELF library's recorded error number can be accomplished by invoking elf_errno() and discarding its return value.

/* clear error */
(void) elf_errno();

Retrieving a human-readable description of the current error number can be done with the following snippet:

int err;
const char *errmsg;
amp;...
err = elf_errno();
if (err != 0)
        errmsg = elf_errmsg(err);

Function elf_errmsg() is not localized.