filehdr(5) File Formats Manual filehdr(5)
Name
filehdr - file header for RISC object files
Syntax
#include < filehdr.h>
Description
Every RISC object file begins with a 20-byte header. The following C struct declaration is used:
struct filehdr
{
unsigned short f_magic; /* magic number */
unsigned short f_nscns; /* number of sections */
long f_timdat; /* time & date stamp */
long f_symptr; /* file pointer to symbolic header */
long f_nsyms; /* sizeof(symbolic header) */
unsigned short f_opthdr; /* sizeof(optional header) */
unsigned short f_flags; /* flags */
};
The byte offset into the file at which the symbolic header can be found is f_symptr. Its value can be used as the offset in to position an
I/O stream to the symbolic header. The ULTRIX system optional header is 56 bytes. The valid magic numbers are given below:
#define MIPSEBMAGIC 0x0160 /* objects for big-endian machines */
#define MIPSELMAGIC 0x0162 /* objects for little-endian machines */
#define MIPSEBUMAGIC 0x0180 /* ucode objects for big-endian machines */
#define MIPSELUMAGIC 0x0182 /* ucode objects for little-endian machines */
RISC object files can be loaded and examined on machines differing from the object's target byte sex. Therefore, for object file magic
numbers, the byte-swapped values have define constants associated with them:
#define SMIPSEBMAGIC 0x6001
#define SMIPSELMAGIC 0x6201
The value in f_timdat is obtained from the system call. Flag bits used in RISC objects are:
#define F_RELFLG 0000001 /* relocation entries stripped */
#define F_EXEC 0000002 /* file is executable */
#define F_LNNO 0000004 /* line numbers stripped */
#define F_LSYMS 0000010 /* local symbols stripped */
See Also
time(2), fseek(3s), a.out(5)
RISC filehdr(5)
