scnhdr(FP)                     6 January 1993                     scnhdr(FP)


 Name

    scnhdr - section header for a common object file

 Syntax


    #include  <scnhdr.h>


 Description

    Every common object file has a table of section headers to specify the
    layout of the data within the file.  Each section within an object file
    has its own header.  The C structure appears below.

    struct  scnhdr
    {
            char               s_name[SYMNMLEN];      /* section name */
            long               s_paddr;               /* physical address */
            long               s_vaddr;               /* virtual address */
            long               s_size;                /* section size */
            long               s_scnptr;              /* file ptr to raw data */
            long               s_relptr;              /* file ptr to relocation */
            long               s_lnnoptr;             /* file ptr to line numbers */
            unsigned short     s_nreloc;              /* # reloc entries */
            unsigned short     s_nlnno;               /* # line number entries */
            long               s_flags;               /* flags */
    } ;

    File pointers are byte offsets into the file; they can be used as the
    offset in a call to fseek (see ldfcn(FP)).  If a section is initialized,
    the file contains the actual bytes.  An uninitialized section is somewhat
    different.  It has a size, symbols defined in it, and symbols that refer
    to it.  But it can have no relocation entries, line numbers, or data.
    Consequently, an uninitialized section has no raw data in the object
    file, and the values for sscnptr, srelptr, slnnoptr, snreloc, and
    snlnno are zero.

 See also

    a.out(FP), fseek(S), ld(CP)