| 知乎专栏 ｜ 多维度架构 |
它的作用：库调用跟踪器。一个库可以包含数百个函数。在这几百个函数中，哪些是我们的二进制程序正在使用的实际函数？
ltrace 命令可以显示运行时从库中调用的所有函数。在下面的例子中，你可以看到被调用的函数名称，以及传递给该函数的参数。你也可以在输出的最右边看到这些函数返回的内容。
ltrace ls
neo@netkiller:~/workspace/Document$ ltrace ls
__libc_start_main(0x407bb0, 1, 0x7fff827aea38, 0x413730, 0x413720 <unfinished ...>
strrchr("ls", '/') = NULL
setlocale(6, "") = "en_US.UTF-8"
bindtextdomain("coreutils", "/usr/share/locale") = "/usr/share/locale"
textdomain("coreutils") = "coreutils"
__cxa_atexit(0x40abb0, 0, 0, 0x736c6974756572, 1) = 0
isatty(1) = 1
getenv("QUOTING_STYLE") = NULL
getenv("LS_BLOCK_SIZE") = NULL
getenv("BLOCK_SIZE") = NULL
getenv("BLOCKSIZE") = NULL
getenv("POSIXLY_CORRECT") = NULL
getenv("BLOCK_SIZE") = NULL
getenv("COLUMNS") = NULL
ioctl(1, 21523, 0x7fff827ae910) = 0
getenv("TABSIZE") = NULL
getopt_long(1, 0x7fff827aea38, "abcdfghiklmnopqrstuvw:xABCDFGHI:"..., 0x00416a60, -1) = -1
__errno_location() = 0x7f89323f16a8
malloc(40) = 0x02543870
memcpy(0x02543870, "", 40) = 0x02543870
__errno_location() = 0x7f89323f16a8
malloc(40) = 0x025438a0
memcpy(0x025438a0, "", 40) = 0x025438a0
malloc(18400) = 0x025438d0
malloc(32) = 0x025434c0
strlen(".") = 1
malloc(2) = 0x025480c0
memcpy(0x025480c0, ".", 2) = 0x025480c0
__errno_location() = 0x7f89323f16a8
opendir(".") = 0x025480e0
readdir(0x025480e0) = 0x02548108
readdir(0x025480e0) = 0x02548120
readdir(0x025480e0) = 0x02548138
readdir(0x025480e0) = 0x02548150
strlen("Tex") = 3
malloc(4) = 0x02550110
memcpy(0x02550110, "Tex", 4) = 0x02550110
readdir(0x025480e0) = 0x02548168
readdir(0x025480e0) = 0x02548188
strlen("makedoc") = 7
malloc(8) = 0x02550130
memcpy(0x02550130, "makedoc", 8) = 0x02550130
readdir(0x025480e0) = 0x025481a8
readdir(0x025480e0) = 0x025481c8
strlen("Docbook") = 7
malloc(8) = 0x02550150
memcpy(0x02550150, "Docbook", 8) = 0x02550150
readdir(0x025480e0) = NULL
closedir(0x025480e0) = 0
free(NULL) = <void>
malloc(72) = 0x025480e0
_setjmp(0x61c040, 0x25480e0, 0x2543af8, 3, 1) = 0
__errno_location() = 0x7f89323f16a8
strcoll("makedoc", "Docbook") = 9
__errno_location() = 0x7f89323f16a8
strcoll("Tex", "Docbook") = 16
__errno_location() = 0x7f89323f16a8
strcoll("Tex", "makedoc") = 7
memcpy(0x025480f0, "\3208T\002", 8) = 0x025480f0
realloc(NULL, 144) = 0x02548130
malloc(168) = 0x025481d0
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550150, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550150, 0x7fff827ac0e0, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550130, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550130, 0x7fff827ac0e0, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550110, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac0e0, 8192, 0x2550110, 0x7fff827ac0e0, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550150, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550150, 0x7fff827ac110, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550150, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550150, 0x7fff827ac050, 0) = 6
fwrite_unlocked("Docbook", 1, 7, 0x7f8931bab780) = 7
__overflow(0x7f8931bab780, 32, 0, 8, 0xffffffff) = 32
__overflow(0x7f8931bab780, 32, 1, 8, 0xffffffff) = 32
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550130, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550130, 0x7fff827ac110, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550130, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550130, 0x7fff827ac050, 0) = 6
fwrite_unlocked("makedoc", 1, 7, 0x7f8931bab780) = 7
__overflow(0x7f8931bab780, 32, 1, 8, 7) = 32
__overflow(0x7f8931bab780, 32, 2, 8, 7) = 32
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550110, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac110, 8192, 0x2550110, 0x7fff827ac110, 0) = 6
__errno_location() = 0x7f89323f16a8
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550110, -1, 0) = 6
__ctype_get_mb_cur_max(0x7fff827ac050, 8192, 0x2550110, 0x7fff827ac050, 0) = 6
fwrite_unlocked("Tex", 1, 3, 0x7f8931bab780) = 3
__overflow(0x7f8931bab780, 10, 0, 120, 3Docbook makedoc Tex
) = 10
free(0x025480c0) = <void>
free(NULL) = <void>
free(0x025434c0) = <void>
exit(0 <unfinished ...>
__fpending(0x7f8931bab780, 0, 0x7f8931bac330, 0x7f8931bac330, 0x25434b0) = 0
fclose(0x7f8931bab780) = 0
__fpending(0x7f8931bab860, 0, 0x7f8931bacdf0, 0, 0x7f89323f17a0) = 0
fclose(0x7f8931bab860) = 0
+++ exited (status 0) +++