Function
elf_cntl() controls the ELF library's subsequent use of the file descriptor used to create ELF descriptor
elf.
Argument
cmd informs the library of the action to be taken:
ELF_C_FDDONE
This value instructs the ELF library not to perform any further I/O on the file descriptor associated with argument elf. For ELF descriptors opened with mode ELF_C_WRITE or ELF_C_RDWR subsequent elf_update() operations on the descriptor will fail.
ELF_C_FDREAD
This value instructs the ELF library to read in all necessary data associated with ELF descriptor elf into memory so that the underlying file descriptor can be safely closed with command ELF_C_FDDONE.
Argument
elf must be an ELF descriptor associated with a file system object (e.g., an
ar(1) archive, an ELF file, or other data file).