cc [ flag ... ] file ... -lelf [ library ... ]
#include <libelf.h>

const char *elf_errmsg(int err);

int elf_errno(void);

If an ELF library function fails, a program can call elf_errno() to retrieve the library's internal error number. As a side effect, this function resets the internal error number to 0, which indicates no error.

The elf_errmsg() function takes an error number, err, and returns a null-terminated error message (with no trailing new-line) that describes the problem. A zero err retrieves a message for the most recent error. If no error has occurred, the return value is a null pointer (not a pointer to the null string). Using err of -1 also retrieves the most recent error, except it guarantees a non-null return value, even when no error has occurred. If no message is available for the given number, elf_errmsg() returns a pointer to an appropriate message. This function does not have the side effect of clearing the internal error number.

Example 1 A sample program of calling the elf_errmsg() function.

The following fragment clears the internal error number and checks it later for errors. Unless an error occurs after the first call to elf_errno(), the next call will return 0.

(void)elf_errno(\|);
/* processing \|.\|.\|. */
while (more_to_do)
{
 if ((err = elf_errno(\|)) != 0)
 {
 /* print msg */
 msg = elf_errmsg(err);
 }
}

See attributes(5) for descriptions of the following attributes:

elf(3ELF), libelf(3LIB), attributes(5)