ar also creates and maintains a table that cross-references
symbol names to the members in which they are defined. The ar command has the following
syntax:
ar {dmpqrtx} [options] [member] archive file [...]
ar creates the archive named archive from the file(s) listed in file. At least one of d, m, p, q, r,
t, and x is required. You will usually use r. Table 29-4 lists the most commonly used ar options.
790
Programming in Linux Part VI
TABLE 29-4
ar Command-Line Options
Option Description
-c Suppresses the warning ar would normally emit if the archive doesn??™t already exist.
-q Adds files to the end of archive without checking for replacements.
-r Inserts files into archive, replacing any existing members whose name matches that
being added. New members are added at the end of the archive.
-s Creates or updates the map linking symbols to the member in which they are defined.
Given an archive created with the ar command, you can speed up access to the archive
by creating an index to the archive. ranlib does precisely this, storing the index in the
archive file itself. ranlib??™s syntax is:
ranlib [-v|-V] file
This generates a symbol map in file. It is equivalent to ar -s file.
The ldd Command
While nm lists the symbols defined in an object file, unless you know what library defines which
functions, it is not terribly helpful.
Pages:
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431