embar — the EmbCC archiver#

embar builds and lists static libraries (.a archives). EmbCC's own C library, C++ library and compiler runtime are packaged with it, so a host needs no binutils or LLVM ar. This page is the command reference.

Synopsis#

embar [-]{r|q}[cSs] ARCHIVE FILE...
embar [-]t ARCHIVE

Description#

embar writes the System V / GNU archive format that embld, GNU ld, lld and the binutils and LLVM tools all read:

the !<arch> signature;
a / symbol index;
a // table for member names longer than fifteen characters;
each member, padded to an even size.

The symbol index lists every global or weak symbol a member defines, and common symbols, for little-endian ELF32 and ELF64 objects. Those are the formats of every target EmbCC compiles for. A member in another format is stored with no index entries. embld does not need the index, because it reads the members themselves; other linkers do.

The output is deterministic. Every member's time, owner and group are 0, and its mode is 644, so the same objects in the same order always give the same bytes, as ar D does in binutils.

A member is named after the file's base name, without its directory.

Options#

The first argument is an operation letter, optionally followed by modifier letters. A leading - is allowed.

`r`#

Insert each FILE into ARCHIVE, replacing a member of the same name in place and appending the others. ARCHIVE is created if it does not exist.

`q`#

Append each FILE, without looking for a member of the same name.

`t`#

Print the members' names, one per line, in archive order.

`c`#

Do not report that the archive was created.

`s`, `S`#

Write the symbol index (s, the default) or leave it out (S).

`D`, `u`, `v`#

Accepted for compatibility with ar, and without effect: the output is always deterministic, and every named file is always written.

Exit status#

0 on success. 1 when a file cannot be read or written, or an existing archive is corrupt. 2 for a usage error.

Examples#

embcc --target=thumbv7em-none-eabi -c a.c -o a.o
embcc --target=thumbv7em-none-eabi -c b.c -o b.o
embar rcs libboard.a a.o b.o
embar t libboard.a
embld -e reset -Ttext 0x0 -Tdata 0x20000000 main.o libboard.a -o fw.elf

The build uses embar for every library unless EMBCC_X86_AR, EMBCC_AARCH64_AR or EMBCC_AR names another archiver.